Adapt upstream MeshCore #3579 at 7457cff43c22697119e06ad7d192a37de0990403:
retain GC1109 LF standby bias, with checked cold controls before band supply
changes and shutdown. Preserve exclusive LF/HF rails and TX error cleanup.
Reset before boot rail changes and before SPI-dependent hard recovery.
Retain our stronger implementation of #3512 at
d208bfef94ab83280de30ba4a0675ff73b3ecef3. Add regressions for suspect FIFO
contents, failed RX_DONE acknowledgement, and fresh preamble timing.
W12 TX power defaults from #3319 were already included via 65aa1138a.
Validation: 79 targeted native tests; canonical W12 Full repeater and Full
Companion builds, capability checks, app-size and RAM checks passed.
Physical W12 RF envelope, current and LoRa management confirmation remain.
Upstream PRs:
https://github.com/meshcore-dev/MeshCore/pull/3579https://github.com/meshcore-dev/MeshCore/pull/3512https://github.com/meshcore-dev/MeshCore/pull/3319