RUI3 v4.2.4 Firmware Update: RAK3172 Flash API & Fixes

March 21, 2026

4.2.4

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What's New in RUI3 v4.2.4

• Added external SPI flash support for RAK3172-F
• Introduced AT+EXTFLSSH command for external flash ID checking
• Added new RUI3 external flash APIs (get/set/erase/info)
• Resolved RAK3172 P2P sleep mode bug
• Fixed Class B AU915 beacon synchronization issue

NOTE

Supported Hardware:

• STM32: RAK3172, RAK3172-SiP, RAK3172LP-SiP, RAK3172-T, RAK11160
• nrf52: RAK4631, RAK3401
• Apollo3: RAK11720

IMPORTANT

LoRaWAN and LoRa P2P API calls have been separated in two different classes since RUI3 v4.1.1..

Old	New	Comment
api.lorawan.pXXX	api.lora.XXX	All LoRa P2P API calls change.
api.lorawan.registerPyyy	api.lora.registerPyyy	All LoRa P2P callback register API calls change.
api.lorawan.nwm.set(1)	api.lorawan.nwm.set()	Set device to LoRaWAN mode.
api.lorawan.nwm.set(0)	api.lora.nwm.set()	Set device to LoRa P2P mode.

Added

No.	Feature
1	Support RAK3172-F which has external SPI flash
2	Add AT+EXTFLSSH for checking external flash ID for production
3	Add RUI API for external flash: api.system.extflash.get(uint32_t addr, uint8_t *buf, uint32_t len) api.system.extflash.set(uint32_t addr, const uint8_t *data, uint32_t len) api.system.extflash.erase(uint32_t addr, uint32_t size) api.system.extflash.info(EXTFLASH_INFO_t *info)

Fixed

Daily Build No. / Bug No.	Description
RUI-1050	[RAK11720] Antenna switch is not powered down when not in RX or TX mode. TX power is too low when joining network.
RUI-1055	[RAK11720] Predefined analog ports are not working.
RUI-1060	LTIME do not go back to zero values after ATZ or hardware reset via RST pin.
RUI-1127	[RUI3 v4.2.4 RAK11720] Add custom BLE characteristic supports only read.
RUI-1154	[ClassB-AU915] The beacon information is incorrect, the node gets stuck at S1.
RUI-1156	[RUI3 v4.2.3 CU-RAK3172-E] sends Confirmed Uplink after Join when AT+CFM=0 in Class C mode.
RUI-1170	[RUI3 V4.2.3] RAK11720 downlinks are lost when LPM=1 is set.
RUI-1171	[RUI V4.2.2] RAK11720 FCC test fail because had noise when using AT+TRTH.
RUI-1172	[RUI V4.2.3] RAK3172, P2P mode, cannot sleep after CAD detected.

Who Should Upgrade to v4.2.4

This update is most relevant for:

• RAK3172-F users needing external SPI flash support
• Projects using LoRaWAN Class B (AU915) requiring improved beacon synchronization stability
• LoRa P2P deployments affected by sleep issues after CAD detection
• RAK11720 applications using custom BLE characteristics

NOTE

RAK3172-F modules ship with RUI3 v4.2.4 preinstalled. Most new deployments using this module do not require a manual upgrade.