[jamesarich]

Checklist

• PR title specifically describes the change
• tools/build_all.py (or CI's board matrix) passes

---

Description of Change

flash_nrf5x_write copied a write into its 4 KB page buffer without checking the page end, so a write crossing a page boundary ran past _fl_buf and its tail never reached flash. It now loops page by page, as Adafruit did in ca46deb. Hardening only: the UF2 path is the only caller and is_uf2_block() accepts just 256 B blocks at 256 B-aligned addresses, which never cross a page.

Tested on the RAK4631 (S140 6.1.1): misaligned blocks are dropped by is_uf2_block() on master and on this branch alike, and aligned app plus 64 KB pattern writes read back with 0 mismatches 3 of 3 times, app booting. A host harness built from the real flash_nrf5x.c writing 64 KB at a 128 B offset shows master losing the 128 B after each of 16 page boundaries (2040-2042 B wrong, overflow abort under fortify) and this branch 0 wrong on 3 seeds.

Summary by CodeRabbit

• Bug Fixes
  • Flash writes that cross a 4 KB page boundary are now handled across the affected pages.
• Documentation
  • Updated the OTAFIX 2.6 changelog to describe page-crossing write behavior and note that the current UF2 workflow uses aligned 256-byte writes that do not cross page boundaries.

[coderabbitai]

No actionable comments were generated in the recent review.

Recent review info

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• Review profile: CHILL
• Plan: Advanced
• Run ID: d00289ec-3b1d-4fac-b96c-d524beaed970

Commits

Reviewing files that changed from the base of the PR and between d9a1fd5 and bae5725.

Files selected for processing: 2

• changelog.md
• src/flash_nrf5x.c

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Walkthrough

flash_nrf5x_write now splits writes across 4 KB page boundaries. The changelog describes this behavior and notes that current UF2 writes use 256-byte blocks at aligned addresses.

Changes: Flash write handling

Layer / File(s)	Summary
Page-spanning write handling src/flash_nrf5x.c, changelog.md	flash_nrf5x_write copies data in page-sized portions and flushes and loads the cache when the write moves to another page. The changelog documents this behavior and the current UF2 write pattern.

Priority: Low

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Bug fix

Suggested reviewers: hathach

Merge Risk: Minimal · up to bae57

The change safely handles cross-page writes without introducing a confirmed merge-blocking risk.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (1 skipped: 1 …	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title clearly and concisely describes the main change: splitting flash writes that cross a flash page boundary.
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 1 functions across 1 files. (1 skipped: 1 unsupported.)

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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_{A rabbit taps the page with care,
Then carries bytes across from there.
The cache is flushed, the next page read,
Each block arrives where writes must lead.
The changelog marks the pathway clear.}

_{Comment @coderabbitai help to get the list of available commands.}