boot_recover.bin, flash_loader_nor.bin and flash_control_info.bin are present in
the same folder as the tool.
We have tried different baud rates, block sizes, offsets, images and programming
options, including both the full firmware image and smaller firmware files. In
every case programming reaches 100% and then fails with the same “fail for
download 0” message. Chip erase continues to work successfully, and the device
enters UART download mode normally afterward.
Could you please advise what might be wrong in our flashing procedure, and what
the correct procedure/command is to successfully program this board?
We first raised this with Realtek support by email and were directed to post here.
Snapshots of the flashing process and error output are attached for reference.
Thank you for the suggestion. I ran the command without the -r option, but the result is the same. The chip erase succeeds and programming reaches 100%, then fails with “fail for download 0”.
Output:
ping ok
ucfg ok
flash loader path …/Pro2_PG_tool_v1.4.3/flash_loader_nor.bin
Uart boot programing [====] 100% 81920/81920 bytes
programing done.
uboot ok
reset device
ping ok
ucfg ok
download to offset 0x0
masked area [0x0, 0x0]
dowload 0, [0x0, 0x4ba000] programing [====] 100% 4980736/4980736 bytes
programing done.
**fail for download 0
download fail
**
Could you please advise what else we can check?
Thanks for sharing the outcome. Could you try the following suggestions?
Try running the command without -x 32, ./uartfwburn.linux -p /dev/ttyUSB0 -f flash_ntz.bin -b 3000000 -U
Reduce baud rate to 2000000 or 1000000
Ensure that AMB82-mini is in download mode, use a reliable USB-to-UART adapter/reliable USB data cable, connected directly to PC USB port — avoid unpowered USB hubs. Please confirm the adapter’s driver is correctly installed and the device appears in your system without error flags.
Thanks for the suggestions. I tried all of them, and the result is still the same.
What I tried:
Removed -x 32
Baud rates 3000000, 2000000 and 1000000
Board in download mode, connected directly to the PC USB port (no hub)
A different USB cable and a different USB port
Setup:
Board: AMB82-Mini (RTL8735B, NOR flash)
SDK: AmebaPro2 SDK (ameba-rtos-pro2), example project realtek_amebapro2_v0_example (GCC-RELEASE)
Image: flash_ntz.bin, 4980736 bytes
Tool: Pro2 PG Tool v1.4.3 (uartfwburn.linux), host PC running Linux
USB-UART: on-board CH340 (1a86:7523), detected by the ch341 driver as /dev/ttyUSB0 with no errors:
usb 3-6: ch341-uart converter now attached to ttyUSB0
We need to check with the tool developer regarding the reason for “fail for download 0”. Meanwhile, would you mind trying the windows variant (uartfwburn.exe) for the download tool?
We suspect the printing of “fail for download 0” might be due to some glitches on log printing. Could you verify if the firmware has been updated successfully using serial monitor?
I mean you can view the logs using a serial monitor. Since you are getting boot errors after download failure, would you mind to share the error logs? To check if the firmware was updated successfully, you may use a serial monitor to view the logs, please press the reset button once to enter “Normal” mode.
Moreover, may we know if this issue only occurs to the board that you are testing with or it applies to every single AMB82-Mini? Could you try verifying this issue using another AMB82-Mini?
Hello KevinKL,
Yes, we used picocom as the serial monitor and captured the following logs. These logs are generated when we simply power on the device; we are not pressing the reset button.
[Normal mode]
BootFromNORFlash
[Start Boot ROM…]
=== Load PARTBL ===
=== Load Done ===
=== Load ISP_IQ ===
[BOOT Err]Invalid Image Mani Label!
[BOOT Err]verify isp mfst failed!!!
=== Load BL ===
[Image Start Table @ 0x18200]
=== Load Done ===
== Boot Loader ==
Nov 4 2025:14:24:05
=== Load FCS Para ===
=== Load Done ===
[BOOT Err]Load ISP IQ fail:0x18
=== Load FW1 ===
FW_ISP_IQ @ 0x8061080, 0x5af80
[BOOT Err]Sensor load fail!162
[BOOT Err]Boot Load Err!,0xe4001b00
[BOOT Err]load img(1) fail!
== Rtl8735b IoT Platform ==
Could you please help us analyze these boot errors, particularly Invalid Image Mani Label, Load ISP IQ fail:0x18, and Sensor load fail!162?
Thank you for the error logs, it is very unusual to see a boot failure. In order to isolate if this is a hardware issue, please try again using another AMB82-mini.
Currently, we have only one AMB82-Mini available, so we are unable to test with another board.
In that case, could you please provide a known-good prebuilt firmware image for the AMB82-Mini, if one is available? We would like to flash the prebuilt image using the same procedure and check whether the board boots successfully.
This would help us determine whether the issue is related to our firmware image or to the flashing/board itself.
You may test with the binary image contained in flash_ntz_f37_mmf2_v1.zip. This firmware is compiled based on the mmf2_video_example_v1_init example. Please flash the prebuilt image using command ./uartfwburn.linux -f flash_ntz.bin -b 3000000 -p /dev/ttyUSB0 -U, you may change the baud rate to 2000000 if needed.
If the boot is successful, you will see the log as shown in log_f37_mmf2_v1
