Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[Unreleased]

[1.0.0] - 2026-05-15

First stable release. The pre-1.0 history below (0.1.0 – 0.113.0) is the incremental record; this entry summarises what v1.0.0 delivers as a whole and what stability commitments come with it.

Stability commitment

  • Public API in lib/include/ubi.h and lib/include/ubi_secure.h is stable. Breaking changes require a major version bump.

  • The on-flash format (plain and secure) is frozen. Future v1.x releases will read v1.0.0 partitions.

  • The Kconfig surface (CONFIG_UBI_*) follows the same compatibility guarantee.

Plain backend (always built)

  • Device lifecycle. Unified ubi_device_init(flash, secure_cfg, &ubi) / ubi_device_deinit() with backend dispatch via an internal vtable. Per-device static memory backend (k_mem_slab) is the default; legacy heap backend is selectable via Kconfig.

  • Volumes. Static and dynamic types, runtime ubi_volume_create / _remove / _resize with grow + shrink, transactional rollback on failure, persistent vol_id high-watermark (IDs are never reused across the device lifetime).

  • LEB I/O. ubi_leb_map / _unmap / _read / _write over the Zephyr Flash Map API, with copy-on-write semantics (old mapping preserved until the new PEB is fully written) and write-block-aligned tail padding using the hardware-reported erase value.

  • Wear-leveling. Global wear budget across all PEBs of a partition; monotonic erase counters with average-tracking; configurable per-write retry count; bad-block torture before isolation.

  • Crash safety. Reserved-PEB dual bank with monotonic vid_sqnum-based recovery; degraded mode that exposes a sticky read-only flag (read_only_degraded) when one bank fails.

  • Mutation gate. A per-device read-only flag is checked before every public mutator; data path, reserved-metadata path, and maintenance path are gated independently.

  • Concurrency. Per-device mutex; multiple ubi_device handles per application supported, each on its own partition; single-handle-per- partition guard rejects double-attach.

  • Misuse handling. All public entry points return -EINVAL with a diagnostic log on NULL arguments instead of asserting; integration bugs are non-fatal in production builds.

Secure backend (CONFIG_UBI_SECURE=y, opt-in)

  • AEAD coverage. AES-128-CCM via PSA Crypto over every commit-visible on-flash structure: device header, volume headers, EC headers, VID headers, reserved PEBs, and LEB payloads. Block location and identity are bound into the AAD, so relocating an authentic record to a different PEB or replaying it under a different volume_id / lnum fails MAC verification.

  • Key hierarchy. HKDF-SHA-256 key derivation, parent-child binding, per-domain child keys, salt generation. Application supplies key material through the get_key_id callback returning psa_key_id_t.

  • Versioned keys & allowlist. Per-PEB key-version refcount; the active write-key version is authenticated on flash; allowlist is enforced on both read and write before any key derivation. Key-life- cycle events KEY_ROTATE_SOON, KEY_ROTATE_NOW, KEY_RETIRABLE are delivered to the application; KEY_RETIRABLE fires only after the last carrier of an old version is recycled.

  • Anti-rollback. Application-supplied check_freshness / sync_freshness callbacks bound to the device-header revision and the VID-header global sequence number — attach-time check plus post-commit sync. Optional CONFIG_UBI_SECURE_SYNC_FRESHNESS_VERIFY re-reads each successful sync to catch ack-but-not-persisted integrations.

  • Counter continuity. Monotonic AEAD counters per LEB, VID, EC, and device-header domain, recovered from flash at attach via a per-volume hidden anchor PEB and a last-writable-witness rule on erase. 48-bit counter saturation fails closed before any flash mutation.

  • Per-domain write budgets. Soft/hard thresholds for each metadata and data domain under the active write key version; reaching the soft threshold emits KEY_ROTATE_SOON, hard threshold emits KEY_ROTATE_NOW, rejects the operation with -ENOSPC, and transitions the device to read-only. Reads remain available.

  • Sticky read-only mode. AEAD failure, RNG failure, or write-budget exhaustion escalates the device to -EROFS-on-write while reads continue. Reset clears the flag.

  • Chunked LEB mode. Optional independently-authenticated 256 B – 64 KiB chunks for large LEBs; only touched chunks are verified on partial read.

  • Coexistence. Plain and secure devices run side by side on different partitions; plain dispatcher returns -ENOTSUP if a non-NULL secure_cfg is passed without CONFIG_UBI_SECURE.

Validated targets

  • Zephyr native_sim (flash simulator) with both 4 KB and 8 KB erase- block geometries, plain + secure + chunked configurations.

  • STM32U585 (b_u585i_iot02a) — 128 KiB UBI partition, plain + secure cross-build verified on every PR.

  • nRF5340 DK (nrf5340dk/nrf5340/cpuapp) — 64 KiB UBI partition, plain + secure cross-build verified on every PR.

Quality bar

  • 55 ZTEST suites, 609 tests (270 plain + 339 secure) covering API contracts, recovery, fault injection (allocation, flash I/O, crypto, RNG, freshness), concurrency, stress, replay-to-other-PEB resistance, forensic scanning, and budget exhaustion.

  • Live coverage reported by Codecov on every push to main.

  • Forensic scanner (scripts/scan_flash.py) verifies that no plaintext data, volume names, or key material appear on flash after secure writes; runs in CI.

  • Build hygiene. format-check, forensic-scan, and per-target cross-build jobs gate every PR; warnings are errors (-Werror -Wextra -Wshadow); test docblocks (\brief, \details, \expected, optional \oracle / \trace / \precondition) are checked in --strict mode.

Resource profile

  • Plain build: ~9.5 KB flash, ~1.5 KB BSS.

  • Secure build: ~28.6 KB flash, ~1.8 KB BSS.

  • Cortex-M33, -Os, STM32U585; UBI library archive only — PSA Crypto and mbedTLS are provided by the platform and not counted.

Documentation

  • Sphinx site under the Furo theme, organised in five Diátaxis- aligned sections (Getting Started, User Guide, Architecture, Reference, Project), deployed to https://kamil-kielbasa.github.io/ubi/.

  • Topic pages: What is UBI?, Comparison vs LittleFS / NVS / ZMS, Concepts at a Glance, Quick Start, Configuration, Cookbook (six end-to-end recipes including STM32U5 / nRF5340 bring-up, A/B firmware, periodic GC, key rotation, freshness store), Plain UBI Workflow, Secure UBI Workflow, Plain Architecture, Secure Architecture, Secure On-Flash Format Specification, API Reference, Kconfig Reference, Error Codes, Glossary, Test Strategy, Contributing.

  • ZTEST traceability tables in Test Strategy link normative behaviours to their regression tests.

Community files

  • SECURITY.md (Private Vulnerability Reporting + email + 7-day acknowledgement SLA).

  • CODE_OF_CONDUCT.md (Contributor Covenant 2.1).

  • CITATION.cff (CFF 1.2.0).

  • .github/ISSUE_TEMPLATE/ — bug, feature, and question forms with a security redirect to SECURITY.md.

  • .github/pull_request_template.md mirroring the contributing-guide PR checklist.

[0.113.0] - 2026-05-14

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.112.0] - 2026-05-14

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.111.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.110.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.109.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.108.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.107.0] - 2026-05-13

Added

  • Per-allocator-kind fault-injection selector in the test API (enum ubi_test_alloc_kind, ubi_test_fault_set_kind_alloc_fail_after()), letting integrators target a specific allocation site without disturbing others. No-op in non-test builds.

[0.106.0] - 2026-05-13

Added

  • Test docblock template recognises optional \oracle, \trace, and \precondition tags; --strict mode promotes them to errors.

[0.105.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.104.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.103.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.102.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.101.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.100.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.99.0] - 2026-05-13

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.98.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.97.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.96.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.95.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.94.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.93.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.92.0] - 2026-05-12

Changed

  • Internal test cleanup; no API or behaviour changes.

[0.91.0] - 2026-05-12

Added

  • Two test-only secure hooks (ubi_secure_test_get_peb_for_lnum, ubi_secure_test_read_vid_meta_from_peb), gated by CONFIG_UBI_CRYPTO_TEST_FAULT_INJECTION.

[0.90.0] - 2026-05-12

Added

  • New Kconfig CONFIG_UBI_CRYPTO_SYNC_FRESHNESS_VERIFY (default n): when enabled, every successful sync_freshness callback is immediately re-checked via check_freshness; a mismatch raises ROLLBACK_POLICY_MISMATCH. Catches integrations that ack the sync but fail to durably persist it.

Changed

  • Internal field grouping in struct ubi_device (e.g. ubi->next_vid_counter → ubi->aead.next_vid). Public struct ubi_device_info is unchanged. No on-flash format change.

[0.89.0] - 2026-05-12

Fixed

  • Stack byte buffers used to build AEAD nonces are now always zero-initialised, eliminating a path that could carry stack garbage into a chunked-LEB nonce.

[0.88.0] - 2026-05-12

Changed

  • AEAD entry points now reject the under-specified case aad == NULL && aad_len != 0 with -EINVAL at the boundary.

  • ubi_secure_destroy_key() now warns when PSA reports an unexpected error so a key-slot leak is no longer silent on cleanup paths.

[0.87.0] - 2026-05-12

Changed

  • Public ABI rename: ubi_secure_get_write_active_key_version → ubi_secure_key_get_active_version in ubi_crypto.h. Call semantics unchanged.

[0.86.0] - 2026-05-12

Changed

  • Erase-time maintenance failures on the per-volume anchor reserve are now reported via LOG_WRN (with PEB index and return code) instead of being silently swallowed.

[0.85.0] - 2026-05-12

Changed

  • Internal refactor of secure AAD builders and LEB I/O signatures. No API, behaviour, or on-flash format change.

[0.84.0] - 2026-05-12

Changed

  • Internal refactor of the secure backend; no behaviour, API, or on-flash format change.

[0.83.0] - 2026-05-12

Changed

  • On-flash record sizes are now compile-time bound to their C structs. A future change that would shift any committed record’s byte count fails the build.

[0.82.0] - 2026-05-12

Changed

  • BREAKING: the secure backend now uses psa_key_id_t for key identifiers throughout its public API. Applications that provide the get_key_id callback (ubi_crypto_get_key_id_cb_t) must update its second parameter from uint32_t * to psa_key_id_t *. No on-flash format change; secure devices attach and continue to operate exactly as before.

[0.81.0] - 2026-05-12

Security

  • Fix AEAD nonce-uniqueness regression in the secure backend. The previous counter-recovery helper only consulted the PEB currently mapped to the requested lnum. After write → unmap → erase-all-dirty → write the new mapping restarted leb_write_counter at 0 under the same HKDF child key, violating AEAD nonce uniqueness for the affected {key_version, volume_id} pair. Versions 0.79.0 and 0.80.0 are vulnerable; do not deploy them.

Changed

  • Per-volume AEAD counter floor is now cached in RAM, reseeded from the anchor plus every authenticated data PEB during attach, bumped before each leb_data_write, and refreshed on anchor rewrite.

  • Anchor witness-check on dirty erase is now O(1) instead of O(N²).

Added

  • New ubi_secure_anchor test suite covering counter inheritance, cold-attach reseed, 48-bit counter saturation, and strict monotonicity loops.

[0.80.0] - 2026-05-11

Changed

  • Plain UBI flow diagrams in Plain UBI Architecture are now a single side-by-side SVG instead of three stacked Mermaid blocks.

[0.79.0] - 2026-05-11

Added

  • New documentation page Comparison: UBI vs LittleFS vs NVS vs ZMS with a side-by-side table and a two-question decision shortcut.

Changed

  • Removed redundant per-page {contents} blocks from Cookbook, Error Codes, and Kconfig Reference (Furo renders a per-page outline).

Fixed

  • Footer GitHub icon now renders as inline SVG so it appears on nested doc URLs.

[0.78.0] - 2026-05-11

Changed

  • Documentation site now uses the Furo theme: light/dark toggle, copy-button on every code block, “Edit on GitHub” links. No content or URLs change.

[0.77.0] - 2026-05-11

Changed

  • Plain UBI Architecture prose now uses the canonical field names volume_id and vid_sqnum (matching the C headers and the Glossary).

Fixed

  • Removed a stale placeholder in the Secure Architecture Overview “What’s next” list.

Added

  • Stylesheet (_static/custom.css) caps Mermaid diagrams at 720 px and centres them.

[0.76.0] - 2026-05-08

Changed

  • The Secure On-Flash Format Specification illustrations are now static SVGs (key hierarchy + attach/runtime sequences) instead of Mermaid; they render identically on GitHub, GitHub Pages, and offline / PDF.

[0.75.0] - 2026-05-08

Added

  • README Acknowledgments section credits the Linux UBI subsystem as the direct inspiration and frames Secure UBI as the author’s addition on top of that foundation.

  • Social preview banner ships in doc/img/.

Changed

  • README release-status note promoted to a top-of-file blockquote; Documentation section now links to the new Glossary.

[0.74.0] - 2026-05-08

Added

  • Single-page Glossary under reference/glossary collects every UBI-specific term used across the documentation.

Changed

  • Plain UBI Architecture now uses the precise field names vid_sqnum and volume_id.

[0.73.0] - 2026-05-08

Changed

  • The Secure On-Flash Format Specification is now a tighter normative reference. Architectural rationale moved to the Secure Architecture Overview and the Secure UBI Workflow guide.

[0.72.0] - 2026-05-08

Added

  • New Plain UBI Workflow guide — when to use plain UBI, the ubi_device lifecycle, volume management, the LEB read/write contract, GC, error handling, degraded read-only mode.

  • New Error Codes reference page listing every value the public API can return with the recommended application reaction.

Fixed

  • Quick Start example: read length now uses sizeof(buf) instead of sizeof(data) (no more silent truncation).

  • Cookbook Periodic garbage collection clarifies that the application’s main TU must contain a matching LOG_MODULE_REGISTER(app).

[0.71.0] - 2026-05-08

Documentation

  • Documentation reorganised into five topic folders (getting_started/, guide/, architecture/, reference/, project/). Old URLs continue to work via redirects.

  • New Kconfig Reference page lists every UBI Kconfig symbol with type, default, range, dependencies, and description.

Changed

  • Reported flash footprint of the UBI library is now ~9.5 KB plain and ~29 KB secure on Cortex-M33 (-Os), measured against the UBI archive only. PSA Crypto / mbedTLS is provided by the platform and not counted.

Fixed

  • key_hierarchy.svg: labels no longer overflow their boxes.

  • onflash_layout.svg: added the missing reserved-PEB zoom.

  • On-flash format spec chapter ordering corrected.

Removed

  • Appendix B and Appendix C of onflash_format_spec.md (covered by project/roadmap.md and the ZTEST traceability tables).

[0.70.0] - 2026-05-07

Changed

  • The Cookbook chapter has graduated from a stub list to six runnable, copy-paste-ready end-to-end recipes: STM32U5 bring-up (b_u585i_iot02a, 128 KiB partition); nRF5340 bring-up (nrf5340dk/nrf5340/cpuapp, 64 KiB partition); A/B firmware slots with a flip volume; periodic GC via k_work; key rotation against PSA from version 1 to version 2 (including when it is safe to call psa_destroy_key()); freshness store on Zephyr Settings with both check_freshness and sync_freshness wired up.

  • Three hero diagrams (stack.svg, onflash_layout.svg, key_hierarchy.svg) promoted from ASCII / Mermaid to hand-authored SVG.

  • README slimmed to its v1.0.0 target shape.

[0.69.0] - 2026-05-07

Changed

  • Secure UBI documentation split along audience boundary into three pages: a normative byte-level reference (onflash_format_spec.md), a developer-onboarding overview (secure_overview.md), and a user-guide workflow page (secure_workflow.md). The three small satellites (volume lifecycle, recovery notes, runtime policy) folded into the spec as chapters 19–21. ZTEST traceability tables moved to test_strategy.md. Old URLs continue to work via redirects.

[0.68.0] - 2026-05-07

Changed

  • Plain Architecture documentation slimmed: removed duplicate ASCII rendering of the PEB lifecycle (Mermaid version retained) and moved the per-file source-code map to a contributor-only Developer Notes page. The legacy Getting Started page split into a hands-on Quick Start and a build/test/coverage section folded into Test Strategy. Old URLs forward to Quick Start.

[0.67.0] - 2026-05-07

Changed

  • Legacy Overview and Introduction pages merged into a single canonical What is UBI? plus a Concepts at a Glance page. The resource-usage profile moved into Plain Architecture alongside the in-RAM data structures it describes. Old URLs forward to What is UBI?.

[0.66.0] - 2026-05-07

Changed

  • Sphinx documentation sidebar reorganised into five Diátaxis-aligned sections (Getting Started, User Guide, Architecture, Reference, Project) with a four-card landing page and a v1.0.0 status banner. Legacy pages remain reachable while content migration completes; sphinx-reredirects keeps every old URL alive.

[0.65.0] - 2026-05-07

Changed

  • Internal test cleanup (consistent section banners, lifecycle hooks). Library, public API, and on-flash format unaffected.

[0.64.0] - 2026-05-07

Changed

  • Secure-backend internal vtable entry points now return -EINVAL with a diagnostic log on NULL arguments instead of tripping an assertion. Production builds without asserts no longer experience undefined behaviour on misuse.

  • Secure onboarding sample now uses Zephyr logging (LOG_INF / LOG_ERR) instead of printk so output can be filtered/silenced.

[0.63.0] - 2026-05-07

Changed

  • Misuse of the public API now logs which argument was invalid (including pointer values for multi-argument checks). Return codes are unchanged.

  • Plain sample now uses Zephyr logging instead of printk.

[0.62.0] - 2026-05-07

Added

  • Cross-reference tables in the secure documentation linking each documented behaviour to the regression test that locks it (recovery scenarios → ZTEST, lifecycle steps → ZTEST, release checklist → ZTEST).

[0.61.0] - 2026-05-07

Added

  • Ready-to-run onboarding sample for the secure backend. Build with west build -p -b <board> sample/ -- -DOVERLAY_CONFIG=boards/secure.conf. CMake automatically selects the secure entry point when CONFIG_UBI_CRYPTO=y.

  • The secure sample is now compile-verified on every PR for the supported Cortex-M targets.

Fixed

  • The library no longer fails to build for downstream consumers that link it without CONFIG_UBI_TEST_API_ENABLE=y (including the new sample).

[0.60.0] - 2026-05-07

Added

  • End-to-end forced-rekey regression test covering eager reserved metadata upgrade, payload survival across rotation, and KEY_RETIRABLE firing exactly when the last stale object is recycled.

[0.59.0] - 2026-05-07

Added

  • Chunked-write 48-bit AEAD counter overflow is proven to fail closed before any flash mutation: returns -EOVERFLOW, emits exactly one KEY_ROTATE_NOW, consumes no PEB.

Changed

  • New test-only API ubi_secure_test_set_leb_write_counter_floor() / _get_leb_write_counter_floor() (gated by CONFIG_UBI_CRYPTO_TEST_FAULT_INJECTION).

[0.58.0] - 2026-05-06

Fixed

  • Restored the native_sim chunked test build (config drift had silently disabled the chunked configuration).

  • Test runner no longer cascades failures: a single test aborting before teardown previously poisoned the rest of the run with misleading allocation failures.

  • Chunked tamper test no longer silently no-ops on roughly half of runs; deterministic destructive write with read-back guard.

  • Coverage-secure CI now matches the runtime contract assumed by the coexistence test (two device handles).

  • Host-side flash forensic scanner (scripts/scan_flash.py) no longer flags ciphertext as a leak.

[0.57.0] - 2026-05-06

Added

  • Plain + secure backend coexistence regression test: a plain device on ubi_partition and a secure device on ubi_partition_2 operate in parallel without state bleed-through and survive a deinit/reattach cycle.

Changed

  • Test build raises CONFIG_UBI_MAX_NR_OF_DEVICES to 2 for the secure native_sim config. Production defaults unaffected.

[0.56.0] - 2026-05-06

Added

  • Replay-to-other-location regression tests: forging an authentic EC, VID, or LEB record into a different physical PEB is rejected by the parent-child AAD binding (peb_index in AAD).

[0.55.0] - 2026-05-06

Added

  • Plain dispatcher test verifying ubi_device_init() returns -ENOTSUP when a non-NULL crypto_cfg is passed but CONFIG_UBI_CRYPTO=n.

Changed

  • ubi_device_init() now rejects, with -EINVAL, a crypto_cfg whose allowed_key_versions contains duplicate entries.

  • Secure attach now rejects, with -EINVAL, a reattach whose requested_write_key_version is below the on-flash write_active_key_version (protects against accidental downgrade and uint8_t wrap-around).

[0.54.0] - 2026-05-06

Added

  • Public API ubi_secure_get_write_active_key_version() returns the authenticated write-active key version of a secure UBI device.

  • Init-time guard: secure init rejects geometries where one reserved generation cannot fit inside one reserved PEB.

Changed

  • LEB write tail padding now uses the flash erased value (typically 0xFF) instead of 0x00, matching what an erase would leave.

  • Documentation note: the secure read path deliberately does not re-verify inner CRC fields after a successful AEAD verification (the CCM tag already covers full record integrity).

[0.53.0] - 2026-05-06

Changed

  • Eager reserved-PEB upgrade on key-version rotation now resets the on-flash and in-RAM VID-domain counter floor to 0. Reattaching with the same key version still preserves the monotonic floor.

  • Reserved-PEB key-version refcount now counts secure volume headers (one per volume on every reserved PEB); the old (kv, vol_count) contribution is released only after the new one has been added.

[0.52.0] - 2026-05-05

Changed

  • Secure read paths reject records with an unknown prefix32.wrapper_version (-EBADMSG), before any key derivation.

  • Single-tag LEB I/O enforces the AES-128-CCM payload limit: ubi_secure_leb_data_write rejects len > 65535 with -EFBIG; the read path rejects data_size > 65535 with -EBADMSG. In non-chunked builds, device init rejects geometries whose leb_size > 65535 with -EINVAL.

Added

  • New constant UBI_SECURE_LEB_SINGLE_TAG_MAX_PAYLOAD (= 65535).

[0.51.0] - 2026-05-05

Added

  • Per-domain write-budget enforcement for all four metadata domains (device header, volume header, EC, VID) under the active write key version, alongside the existing per-LEB data budget. Reaching CONFIG_UBI_CRYPTO_ROTATE_SOON_PCT of any budget emits KEY_ROTATE_SOON; reaching CONFIG_UBI_CRYPTO_ROTATE_NOW_PCT emits KEY_ROTATE_NOW, rejects the operation with -ENOSPC, and transitions the device to read-only. Reads remain available throughout.

[0.50.0] - 2026-05-04

Changed

  • Plain backend: public API functions now return -EINVAL with a log message on NULL arguments instead of triggering a kernel assert.

  • Plain backend: error paths now emit LOG_ERR for diagnostics.

  • Plain backend: reserved-PEB overwrite fixed a dual-bank safety issue where a replacement PEB could be re-erased within the same commit.

[0.49.0] - 2026-05-04

Changed

  • API rename: struct ubi_mtd → struct ubi_flash_desc, .mtd → .flash field across the codebase.

  • Kconfig rename: CONFIG_UBI_CRYPTO_MAX_ALLOWLIST_LEN consolidated into CONFIG_UBI_CRYPTO_MAX_KEY_VERSIONS; CONFIG_UBI_MEM_STATS → CONFIG_UBI_TEST_MEM_STATS.

  • UBI_CRYPTO now depends on MBEDTLS_ENTROPY_POLL_ZEPHYR.

[0.48.0] - 2026-04-17

Added

  • Monotonic AEAD counters for EC and device-header domains (recovered from flash during init, incremented per write).

  • VID counter overflow check (COUNTER_MAX) emits KEY_ROTATE_NOW.

  • Eager reserved-PEB key upgrade during attach: when requested_write_key_version differs from flash, reserved metadata is rewritten under the new key immediately (graceful fallback if the key is not yet provisioned).

  • Reserved-PEB refcount tracking: KEY_RETIRABLE is withheld while reserved PEBs still depend on the old key version.

Changed

  • Secure crypto: central allowlist check now in derive_domain_key() and derive_leb_key() — all domains and both read/write paths validated before key derivation.

[0.47.0] - 2026-04-17

Changed

  • Internal cleanup (file renames, sensitive-buffer zeroization via mbedtls_platform_zeroize); no API or behaviour changes.

[0.46.0] - 2026-04-17

Added

  • Functional parity test coverage for the secure backend (device init/deinit, volume CRUD, LEB I/O, resize, edge cases) mirrored from the plain backend, plus secure fault-injection, mutation-gate, and vol-id-watermark suites.

[0.45.0] - 2026-04-16

Changed

  • Documentation aligned with secure backend implementation: refreshed flash footprint, struct sizes, test counts, coverage numbers, and Kconfig reference across all docs.

Fixed

  • CI: clang-format version-dependent goto label formatting handled with off/on guards.

  • CI cross-build nRF5340 secure: added test random generator for builds without BLE IPC.

  • CI cross-build STM32U5 secure: ubi_device size BUILD_ASSERT guarded for ARM vs POSIX k_mutex layout difference.

[0.44.0] - 2026-04-16

Added

  • Forensic scan test suite: verifies no plaintext data, volume names, or key material appear on flash after secure writes.

  • Host-side Python forensic scanner (scripts/scan_flash.py) and test docblock checker scripts.

  • CI jobs: format-check, forensic-scan, cross-build secure for STM32U5 and nRF5340.

  • Init-time anchor re-creation: orphaned volumes automatically get a new hidden anchor at attach.

Changed

  • Test and coverage scripts accept a mode parameter (plain / secure / chunked).

[0.43.0] - 2026-04-16

Added

  • Chunked secure LEB mode: LEB records split into independently authenticated chunks for partial-read support. Configurable chunk size (256–65536 B). Only touched chunks are verified, reducing read latency and RAM.

  • Chunked geometry validation at init and budget accounting for chunked writes.

  • Secure recovery test suite: interrupted writes, anchor rewrites, reserved-PEB commit faults, generation replay rejection.

  • Flash write fault injection wired into the secure backend.

[0.42.0] - 2026-04-15

Added

  • Sticky crypto read-only mode: the event callback can escalate to a device-wide write block (-EROFS); reads remain functional.

  • Security event infrastructure: 10 event types (AUTH_FAILURE, FORMAT_VIOLATION, KEY_ROTATE_SOON/NOW, KEY_RETIRABLE, RNG_FAILURE, etc.) delivered through the application callback.

  • Freshness sync after every commit-visible mutation with configurable cadence.

  • Key-version PEB refcount tracking with KEY_RETIRABLE signalling when a key version is fully erased.

  • LEB usage budget tracking with soft/hard thresholds and pre-write rejection.

  • Read-path key-version allowlist enforcement.

  • Sensitive-buffer zeroization (compiler-safe volatile memset).

[0.41.0] - 2026-04-15

Added

  • Hidden per-volume anchor PEBs: each secure volume reserves one internal PEB preserving monotonic counter state across unmap, shrink, and erase.

  • VID-domain counter floor: monotonic VID counter persisted in the secure device header, reconstructed at attach.

  • Last-writable-witness check: the erase path rewrites the anchor before erasing the last carrier of a volume’s counter floor.

  • Emergency free-PEB reserve: write path reclaims a dirty PEB before consuming the last free PEB.

Changed

  • Volume create rolls back on anchor allocation failure.

  • New docs: secure volume lifecycle and secure recovery scenarios.

[0.40.0] - 2026-04-15

Added

  • Complete secure data-PEB runtime: volume create / resize / remove, LEB write / read / map / unmap, erase — all with authenticated encryption.

  • Data-PEB scan pipeline: classifies PEBs into free/dirty/bad pools with full AEAD verification.

  • Functional parity test coverage with the plain backend on encrypted flash.

  • Flash geometry overlays for nRF5340 (4 KB erase) and STM32U5 (8 KB erase) on native_sim; multi-geometry CI runs.

Fixed

  • LEB write/nonce counters now recovered from existing VID header (were hardcoded to 0).

  • Write-block alignment padding for the secure ciphertext+tag buffer.

  • Missing bad-block torture and degraded-mode recovery in the secure runtime.

  • Geometry validation for erase/write block alignment.

[0.39.0] - 2026-04-14

Added

  • First secure backend release: authenticated read/write for EC headers, VID headers, and LEB data in single-tag mode.

  • Domain-separated AAD serialisation for all record types.

Changed

  • Key derivation centralised; parent authentication passed via typed context structs.

[0.38.0] - 2026-04-15

Added

  • Secure reserved-PEB attach path: format-on-blank, attach-to-existing, mode-mismatch detection.

  • PSA Crypto integration: HKDF-SHA-256 key derivation, AES-128-CCM AEAD, salt generation.

  • Encrypted dual-bank reserved-PEB commit and authentication.

[0.37.0] - 2026-04-14

Added

  • Secure public API surface: crypto config, event types (tagged union), freshness descriptor, policy struct, and callback typedefs.

  • Secure Kconfig surface: master enable, budget limits, rotation thresholds, chunked mode, PEB cache, freshness sync, strict RO policies.

  • Crypto fault-injection hooks (7 stages) for integration tests.

  • Secure test profiles and board configs with mbedTLS PSA.

[0.36.0] - 2026-04-14

Changed

  • Backend dispatch: every public API function now routes through an 11-op vtable. Plain backend functions renamed to ubi_plain_*. Internal headers decoupled from plain-specific includes, making them backend-agnostic.

[0.35.0] - 2026-04-14

Changed

  • Unified init API: ubi_device_init(flash, crypto_cfg, &ubi). Passing NULL selects plain; non-NULL selects secure. Runtime backend dispatch via the ops vtable.

[0.34.0] - 2026-04-13

Changed

  • Secure architecture spec: per-device runtime mode selection (not per-build), tagged-union events, check_freshness confirmed as attach-time only.

  • Repository layout split into common/, plain/, secure/ namespaces for library and test sources.

  • format.sh is now recursive with --check mode for CI.

[0.33.0] - 2026-04-11

Changed

  • design_proposal_crypto.md promoted to secure_architecture.md as a first-class architecture document.

  • architecture.md renamed to plain_architecture.md.

[0.32.0] - 2026-04-11

Changed

  • Secure architecture spec rewrite (v6): hidden per-volume anchor PEBs, secure device header with crypto metadata, full counter continuity framework, renamed child keys to domain names, simplified chunked mode, expanded write-budget enforcement, precise AAD byte layouts, tagged-union events with verdicts.

[0.31.0] - 2026-04-10

Changed

  • Secure architecture spec rewrite (v5): mode detection rules, normative KDF labels, single-tag CCM payload limit, zero-length LEB encoding, tail-padding rules, parent EC key_version in VID and LEB AAD.

[0.30.0] - 2026-04-09

Added

  • “Why UBI for Zephyr” positioning document: gap analysis, comparison with FCB / NVS / ZMS / LittleFS.

Changed

  • Secure architecture spec rewrite (v4).

[0.29.0] - 2026-04-09

Added

  • Persistent vol_id high-watermark: volume IDs are never reused across the device lifetime. Overflow returns -ENOSPC.

Changed

  • Volume matching by vol_id instead of positional index; re-index loop eliminated.

[0.28.0] - 2026-04-09

Added

  • Central mutation gate: per-device read-only flag checked before every public mutator. Three mutation classes (reserved metadata, data path, maintenance).

  • Runtime degradation detection and self-healing via reserved-PEB bank recovery.

  • Test-only write-shutdown API.

[0.27.0] - 2026-04-10

Changed

  • Data-PEB commit order changed to EC → DATA → VID. The VID header is now the sole commit-visible record.

  • Init scan distinguishes free PEBs from uncommitted writes by probing the data area.

Fixed

  • Uncommitted writes were misclassified as free under the new write order.

[0.26.0] - 2026-04-09

Changed

  • Erased-state detection now uses the hardware-reported erase value instead of a hard-coded 0xFF.

[0.25.0] - 2026-04-08

Changed

  • Secure architecture spec rewrite (v3): init classification, write/read/erase paths, key lifecycle with refcount retirement, events and policy, cost model, illustrative API (Appendix A).

[0.24.0] - 2026-04-03

Added

  • Secure architecture design proposal (v2): AES-128-CCM for all on-flash structures, ESSIV nonces, per-domain key derivation, anti-rollback, crash-safe key rotation, external AAD callback.

[0.23.0] - 2026-04-03

Added

  • nRF5340 DK board support (64 KB UBI partition, 4 KB erase blocks).

Changed

  • CI split into parallel jobs (native-tests, cross-build, coverage) with concurrency control, least-privilege permissions, path filters, and SHA-pinned actions.

[0.22.0] - 2026-04-02

Added

  • Flash I/O fault injection: controllable write and erase failures.

  • New regression coverage: ubi_io_faults, ubi_init_errors, plus 34 new error-handling and 6 new recovery tests.

  • Long-term EC counter equality test (500 cycles, max deviation ≤ 2).

[0.21.1] - 2026-04-02

Fixed

  • Sphinx -W: warnings now fail the doc build.

  • Breathe + Doxygen 1.9.8 compatibility (switched to doxygengroup directives).

[0.21.0] - 2026-04-02

Added

  • Static memory backend (default): all allocations via k_mem_slab pools instead of the global heap.

  • Memory abstraction layer with Kconfig-selectable backend (static / heap).

  • Init-time validation: static backend verifies flash geometry fits configured pools.

  • Dual-backend CI runs.

Changed

  • PEB tracking items share a union for in-place retyping during state transitions.

  • Fault injection routed through the memory abstraction layer.

[0.20.1] - 2026-04-02

Changed

  • Removed read-write lock from roadmap (per-device mutex is sufficient).

  • Renamed “User-space tools” to “Shell commands” in roadmap.

Fixed

  • Test API functions now visible in Doxygen output.

[0.20.0] - 2026-04-01

Added

  • Single-handle-per-partition guard: prevents two device handles for the same flash partition.

  • Concurrency test suite: multi-threaded readers/writers, deinit quiescence, double-init guard.

Fixed

  • ubi_device_deinit() acquires the mutex before teardown, preventing races with in-flight operations.

[0.19.0] - 2026-04-01

Added

  • Volume config validation, device/volume header semantic checks.

  • Invariant checker API for tests.

  • Allocation fault injection via Kconfig.

  • Shared test fixtures and raw flash write helpers.

Changed

  • Transactional ubi_volume_create() and shrink: RAM state consistent with flash on failure.

  • Copy-on-write leb_write(): old mapping preserved until the new PEB is fully written.

  • ubi_leb_unmap() is idempotent; ubi_leb_map() is a no-op when already mapped.

Fixed

  • PEB tracking loss on allocation failure during bad-block handling.

[0.18.0] - 2026-04-01

Added

  • Overview doc with mental model, six-step lifecycle, and Mermaid diagrams.

  • Architecture guide expanded: core invariants, Mermaid flowcharts, degraded-mode table.

Changed

  • README rewritten as a landing page with stack diagram, key properties, quality metrics.

  • All doc pages restructured with “what this page covers” framing.

[0.17.1] - 2026-03-31

Fixed

  • Doc source-file table and test counts aligned with file splits.

  • Sample app expanded to demonstrate the full lifecycle.

[0.17.0] - 2026-03-31

Changed

  • Internal source file split (ubi_core.c into init + runtime, ubi_io.c into metadata + data). No functional changes.

[0.16.0] - 2026-03-31

Added

  • read_only_degraded exposed in the device-info struct.

  • Cached geometry in the device struct (no flash I/O for get_info()).

  • Thread-safety notes and precise \retval docs on all public functions.

Changed

  • allocated_peb_count renamed to reserved_peb_count.

  • -EROFS propagated from the degraded reserved-PEB scan through init and mutators.

[0.15.0] - 2026-03-31

Added

  • Volume name validation helpers (bounded, NUL-safe).

  • Semantic validation of on-flash device headers.

  • Flash geometry validation at init.

Fixed

  • Eliminated strlen() on raw flash fields (memory safety).

  • Sequence number monotonicity: global_sqnum set to max + 1 after scan.

  • Volume headers always read from the highest-revision reserved PEB.

  • Reclaim error paths no longer leak PEBs.

[0.14.0] - 2026-03-30

Changed

  • Reserved PEB module renamed with ubi_flash_res_peb_* prefix.

  • Volume module deduplicated with shared helpers.

[0.13.0] - 2026-03-30

Added

  • Bad-block torture test with configurable cycles and per-PEB erase attempts.

  • Runtime average erase counter tracking.

Fixed

  • Use-after-free in leb_write() write-fail path.

  • Bad-block paths now update erase counter averages.

[0.12.0] - 2026-03-30

Added

  • Configurable write retry count for data PEBs (CONFIG_UBI_PEB_WRITE_RETRY_COUNT).

Fixed

  • Write failure in leb_write() now properly marks the PEB as bad.

[0.11.0] - 2026-03-27

Added

  • Initial crypto layer design proposal (AES-128-CCM via PSA Crypto API).

[0.10.0] - 2026-03-27

Added

  • Reserved-PEB management extracted into a dedicated module.

  • Configurable reserved-PEB count (2–4) for cold-spare support (CONFIG_UBI_DEV_HDR_NR_OF_RES_PEBS).

[0.9.0] - 2026-03-26

Changed

  • Monolithic source restructured into core, volume, LEB, I/O, and cache modules.

  • Init scan decomposed into 5 helpers.

  • Overhauled Doxygen and Kconfig.

Fixed

  • 11 bugs from a code-quality audit.

  • Memory leak in duplicate-LEB resolution.

[0.8.0] - 2026-03-25

Added

  • Sphinx documentation with the Read the Docs theme, deployed to GitHub Pages.

  • Doxygen + Breathe auto-generated API reference.

  • Architecture guide, Getting Started, Configuration reference, Contributing guide.

[0.7.0] - 2026-03-25

Added

  • native_sim board support.

  • Test suites: error handling, boundary, recovery, stress.

  • GitHub Actions CI with build, test, and Codecov.

  • Coverage infrastructure and CI scripts.

  • Test strategy documentation.

Fixed

  • west.yml: cmsis_6 renamed to cmsis for Zephyr v4.0.0.

[0.6.0] - 2026-03-24

Added

  • Architecture guide with ASCII diagrams (on-flash layout, PEB lifecycle, init flow, wear-leveling).

  • Development roadmap and contributor guide.

Fixed

  • EBA table corruption during init when resolving sequence-number conflicts.

[0.5.0] - 2025-09-25

Added

  • Mutex-based synchronisation for thread-safe operations.

[0.4.0] - 2025-09-24

Added

  • Sample application for STM32U5.

Changed

  • Optimised flash I/O and improved logging.

[0.3.0] - 2025-09-21

Added

  • .clang-format configuration.

Changed

  • Migrated from low-level flash APIs to the Zephyr Flash Map (Flash Area API).

[0.2.0] - 2025-09-10

Added

  • Volume support with static and dynamic types.

  • Runtime resizing, write-block alignment, partial dual-bank support.

  • Hardware tests on STM32U5.

[0.1.0] - 2025-07-25

Added

  • Initial release: device init/deinit, LEB I/O (map, unmap, read, write), PEB statistics.

  • Hardware integration tests and sample application for STM32U5.