AT+BOOT Not working as expected?

Hi all,
I’m just started working with the RAK3272-SiP Breakout Board. I updated the firmware to the latest RUI3 published version v4.1.0.
The breakout board is connected to my computer through a 3V3 TTL cable from FTDI and I use the Teraterm application to send and receive AT commands.
I’ve tested the AT BOOT command, but I cannot see the expected result. According to the documentation, after the AT+BOOT command I should see a , but in my case I only see wrong printed characters.

RAKwireless RAK3272-SiP

Version: RUI_4.1.0_RAK3272-SiP
Current Work Mode: LoRaWAN.

It seems that the system enters in boot mode or something, but it is not keeping the 115200bps baud rate.
I’m probably not using correctly the AT boot command, but I cannot find what I’m doing wrong.
Any help about this?
Thank you so much.

Welcome to RAK forum @dbagan ,

I’ve checked it on my RAK3272-SiP board but I cannot see scrambled characters.


I am not sure on the status of your module if it has custom FW, etc. But if you are sure that is not because of the USB-UART converter or serial terminal, one thing you can do is full erase the chip using STM32CubeProgrammer then reupload the RUI3 hex firmware.

Hi Carlrowan,
Many thanks for your response.
I’m using the stock firmware from RAK (RAK3272-SiP_latest_final.hex) and I flashed using the STM32CubeProgrammer. I also erased all the flash before re-flashing the stock firmware again.
I’ve checked to enter into boot mode again using the WisToolBox v1.4.4 in console mode and it works, so it must be something wrong with TeraTerm.
Really sorry for this basic mistake.
Thank you so much for your help.

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