fix(lr2021): live LF↔HF reconfigure via full begin()

[Ethan-chen1234-zy]

Summary

• On develop, LoRa region changes apply live via reconfigure() (no reboot).
• LR2021 incremental setOutputPower across Sub-GHz ↔ 2.4 GHz can return RadioLib -706; the old assert HardFaulted before config save.
• Detect LF↔HF hops (carrier crosses 1500 MHz) and call lora.begin(...); same-band changes stay on the incremental path. Power failures are logged + CRITICALERROR instead of asserting.

Scope

• src/mesh/LR20x0Interface.cpp only (USE_LR2021).
• No board variants / PA tables.
• Does not affect cold boot (init() → begin()), non-LR2021 radios, or same-band live reconfigure.

Test plan

• Sub-GHz → live set lora.region=LORA_24: log LF/HF band hop ... full begin(), no -706 / reset; region persists.
• Live switch back to a Sub-GHz region: same checks.
• Same-band region/power change still works.
• Cold boot already in LORA_24 still OK.
• Verified on internal LR2021 dual-band HW; please spot-check other USE_LR2021 boards if available.

Summary by CodeRabbit

• Bug Fixes
  • Improved radio reconfiguration when moving between low- and high-frequency bands.
  • Applies the correct initialization steps, including clock/RF switching, CRC, and RX gain settings, on band hops.
  • Streamlined reconfiguration for same-band updates with enhanced failure handling.
  • Radio RX now reliably restarts after successful frequency changes.
  • More consistently retains and reuses the active carrier frequency across initialization and subsequent reconfigurations.

[github-actions]

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Warning

This is an automated, unreviewed CI test build. Back up your device configuration
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Supported boards built by this PR (31)

	Device	Board	Platform
	Crowpanel Adv 3.5 TFT	elecrow-adv-35-tft	esp32-s3
	Heltec HT62	heltec-ht62-esp32c3-sx1262	esp32-c3
	Heltec Mesh Node 096	heltec-mesh-node-t096	nrf52840
	Heltec Mesh Node T1	heltec-mesh-node-t1	nrf52840
	Heltec Mesh Node T114	heltec-mesh-node-t114	nrf52840
	Heltec V3	heltec-v3	esp32-s3
	Heltec V4	heltec-v4	esp32-s3
	Meshnology W10	meshnology_w10	esp32-s3
	Meshnology W12	meshnology_w12	esp32-s3
	Raspberry Pi Pico	pico	rp2040
	Raspberry Pi Pico W	picow	rp2040
	RAK WisMesh Pocket V3	rak_wismesh_pocket	nrf52840
	RAK WisMesh Pod	rak_wismesh_pod	nrf52840
	RAK WisMesh Repeater Mini V2	rak_wismesh_repeater_mini	nrf52840
	RAK WisMesh Tag	rak_wismeshtag	nrf52840
	RAK WisBlock 11200	rak11200	esp32
	RAK WisBlock 11310	rak11310	rp2040
	RAK3312	rak3312	esp32-s3
	RAK WisBlock 4631	rak4631	nrf52840
	Seeed SenseCAP Mesh-Tracker-X1	seeed_mesh_tracker_X1	nrf52840
	Seeed Wio Tracker L1	seeed_wio_tracker_L1	nrf52840
	Seeed Xiao NRF52840 Kit	seeed_xiao_nrf52840_kit	nrf52840
	Seeed Xiao ESP32-S3	seeed-xiao-s3	esp32-s3
	Station G2	station-g2	esp32-s3
	Station G3	station-g3	esp32-s3
	LILYGO T-Deck	t-deck-tft	esp32-s3
	LILYGO T-Echo	t-echo	nrf52840
	LILYGO T-Echo Plus	t-echo-plus	nrf52840
	LILYGO T-Impulse Plus	t-impulse-plus	nrf52840
	LilyGo T3-C6	tlora-c6	esp32-c6
	Seeed SenseCAP T1000-E	tracker-t1000-e	nrf52840

Build artifacts expire on 2026-08-29. Updated for 1f431a0.

[coderabbitai]

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• src/mesh/LR20x0Interface.cpp

🚧 Files skipped from review as they are similar to previous changes (1)

• src/mesh/LR20x0Interface.cpp

---

📝 Walkthrough

Walkthrough

LR20x0Interface tracks the programmed frequency, performs full initialization when switching LF/HF bands, and uses incremental radio updates for same-band reconfiguration while restarting reception and recording failures.

Changes

Radio reconfiguration

Layer / File(s)	Summary
Frequency tracking and initialization src/mesh/LR20x0Interface.cpp	Adds last-frequency tracking and records the current frequency during initialization.
Band-aware reconfiguration src/mesh/LR20x0Interface.cpp	Uses full lora.begin() initialization for LF/HF transitions and incremental parameter updates for same-band changes, with RX restart and error recording on failures.

Estimated code review effort: 4 (Complex) | ~45 minutes

Sequence Diagram(s)

sequenceDiagram
  participant LR20x0Interface
  participant lora
  participant RX
  LR20x0Interface->>LR20x0Interface: Compare requested and previous frequency bands
  LR20x0Interface->>lora: Run full begin() for a band hop
  lora-->>LR20x0Interface: Return initialization result
  LR20x0Interface->>RX: Restart reception
  LR20x0Interface->>lora: Apply incremental settings within the same band
  lora-->>LR20x0Interface: Return parameter results
  LR20x0Interface->>RX: Restart reception

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Possibly related PRs

• meshtastic/firmware#10567: Both modify LR20x0 initialization and reconfiguration behavior.
• meshtastic/firmware#11138: Both modify LR20x0 initialization around lora.begin().

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The description covers summary, scope, and test plan, but it omits the required attestations checklist from the template.	Add the attestations section with the required test checkboxes and note whether hardware-specific verification was completed.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title is concise and accurately reflects the main change: live LF↔HF reconfigure now uses full begin() on band hops.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 1

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@src/mesh/LR20x0Interface.cpp`:
- Around line 193-225: Update the band-hop branch around lora.begin() to mirror
init()’s LF/HF reinitialization: apply the appropriate RF-switch GPIO state for
the new frequency, wait for TCXO settling, retry SPI command failures after the
established delay, and retry without TCXO for TCXO_OPTIONAL when applicable.
Replace the ignored setCRC, setRfSwitchTable, and setRxBoostedGainMode results
with the same error checking and logging used by init() and the same-band path,
preserving failure returns and critical-error handling.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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📒 Files selected for processing (1)

• src/mesh/LR20x0Interface.cpp

[thebentern]

@Ethan-chen1234-zy please run trunk fmt. Thanks

[Ethan-chen1234-zy]

Done — ran trunk fmt and pushed. Thanks.

[caveman99]

#11234 Addresses the same code area and a very similar problem. I think the underlying issue is the same here. Can you try with this patch so we don't fix the same thing twice?

[Ethan-chen1234-zy]

@caveman99 Thanks — I tried #11234 alone on LR2021 dual-band HW (live US → LORA_24).

#11234 alone avoids HardFault, but setOutputPower still fails while prefs save region=LORA_24. RF stays broken even after switching back to US (until reboot / cold begin()):

INFO | Set radio: region=LORA_24, name=LongFast, config=0, ch=25, power=10
INFO | frequency: 2420.718750
INFO | Final Tx power: 10 dBm
ERROR | NOTE! Record critical error 7 at src/mesh/LR20x0Interface.cpp:215

This PR (#11279) on the same live hop takes the full begin() path and TX works:

INFO | Set radio: region=LORA_24, name=LongFast, config=0, ch=25, power=10
INFO | frequency: 2420.718750
INFO | Final Tx power: 10 dBm
INFO | LR20x0 LF/HF band hop 906.9 -> 2420.7 MHz, full begin()

So #11234 and #11279 are complementary, not duplicates: #11234 softens asserts / SPI hang; #11279 is still required for correct live LF↔HF reconfigure. Happy to rebase after #11234 lands if needed.

[RCGV1]

I opened a focused companion PR against this branch: Ethan-chen1234-zy#1

It fixes a MHz/Hz mismatch in the external LF/HF RF-switch GPIO selection, propagates rejected reconfiguration steps instead of restarting RX and returning success, and adds LF/HF boundary plus bidirectional transition tests. meshnology_w12 builds successfully.

I do not have LR2021 hardware attached. The remaining useful check is the same live US -> LORA_24 -> US matrix on your dual-band device, verifying actual TX/RX in both directions and no new critical radio error.