fix: carry across octets when computing the nRF DFU MAC (+1) (§4)#110
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find_nrf_dfu_device incremented only the last MAC octet with (+1 & 0xFF), so a device whose address ends in 0xFF produced ...:EE:00 instead of carrying into the previous octet (...:EF:00). The bootloader then advertised at an address the scanner never matched, causing a silent 30 s scan failure. Increment the full 48-bit address with carry (extracted to a tested _increment_mac helper). Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01JRrm95f1qNZzDM9r2SB6KW
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Summary
find_nrf_dfu_deviceMAC+1 wrapped without carry (🟡)The nRF DFU bootloader advertises at
original_address + 1. The code incremented only the last octet with(+1) & 0xFF, so an address ending in0xFFbecame…:EE:00instead of carrying into the previous octet (…:EF:00). The bootloader then advertised at an address the scanner never matched → a silent 30 s scan failure on those devices.Fix
Increment the full 48-bit address with carry, extracted into a small, tested
_increment_machelper.Test plan
uv run pytest -q→ 447 passed (new parametrized carry test:…EE:01→…EE:02,…EE:FF→…EF:00,…FF:FF→…DE:00:00… wait double-carry,FF:…FF→00:…00; updated an existing test that encoded the old no-carry behavior)ruff,mypyclean🤖 Generated with Claude Code