Bricked Xiao ESP32-C3 can't flash new code or bootloader

Products & Technology XIAO
1

I have a Xiao ESP32-C3 that exhibits all of the same symptoms as this case here:

I’ve been updating code for my board over the last few days, and finally messed up by calling rmt_driver_install() twice in my setup function. The ESP32-C3 is now stuck in an infinite boot, abort (crash), and reboot loop. I can see the reboot cycle happening over the serial monitor. When I try to upload code, I always encounter the dreaded
A serial exception error occurred: Write timeout
problem. I’ve tried:

1.) Making sure the ESP32-C3 is entering bootloader mode by holding down the boot button while powering on the device. I know I’m doing it right because this has solved my boot issues in the past.
A serial exception error occurred: Write timeout
If I don’t hold down the boot button, then I get
A fatal error occurred: No serial data received.

2.) Reflashing the bootloader. The write timeout prevents this from happening as well.

> ERROR:Write timeout
> WARNING:Sync fail...

3.) Forcing GPIO2 low. Holding GPIO2 at ground from power-up to code upload doesn’t change anything.
4.) Forcing GPIO2 high. Holding GPIO2 at 3.3V from power-up to code upload doesn’t change anything.

Nothing is connected to GPIO2.

5.) Restarting PC and updating the drivers for ‘USB JTAG/serial debug unit’ in device manager.

Is it bricked for good?

2

The following steps may be helpful

  1. Is “USB JTAG/serial debug unit” listed under “Universal Serial Bus Devices” in the Device Manager?
    Note: not “Ports (COM & LPT)”.
  2. If not, this method does not work.
  3. If so, right click “USB JTAG/serial debug unit” and “Update Driver”
  4. select “Browse my computer for drivers”
  5. select “Let me pick from a list of available drivers on my computer”
  6. select “USB Serial Device” and click “Next”

If you are lucky, it will be restored.

2 Likes
3

Incredible. I thought there was no way it was a driver problem, because I had flashed code dozens of times just minutes before the board went AWOL. Also, I had done the exact steps you described less than 24 hours ago when troubleshooting a similar problem.

But, I did it again right now, and successfully recovered the device. You’re a lifesaver in this forum. Thank you!

1 Like
4

awesome… you always find the answer in the last place you look…lol

1 Like
5

Hi guys, Thanks for the suggestion.

I followed your instructions and tried updating the driver manually. However, even after selecting “USB Serial Device” from the list, it still shows up as “USB JTAG/serial debug unit” in Device Manager.

I also tried flashing the official factory firmware using EspRFTestTool, following Seeed’s guide. I held the BOOT button while connecting the board to USB, and then attempted to load the official .bin file but unfortunately I still get this error.

ERROR:Write timeout
WARNING:Sync fail…

At this point, I’ve tried multiple cables, different USB ports, and even different PCs, I updated the Driver per @nblanch 's suggestion but the issue remains.

Any other ideas would be greatly appreciated!

6

Hi there,

You may try , Openning the device manager and right click on Jtag or USb device ,then click update the driver. Note what is says it is, download seeed’s driver and , choose let me pick the driver file and navigate to the seeed driver and select that. reboot and try again,

Also ZADIG can be used to change the drivers may be easier.

HTH
GL :slight_smile: PJ :v:

I plugged in a C3 and here is what this looks like.

ESP32c3_port_device2
ESP32c3_port_device21270×1365 208 KB

ESP32c3_port_device
ESP32c3_port_device2241×1670 443 KB

7

I wonder if that debudder unit would help with this

8

Hi there, Probably NOT. The ports are always the gating issue on plug and Play or Plug and PRAY :pray: with this stuff sometimes.

let’s see what he finds.
:+1:

GL :slight_smile: PJ :v:

9

Hi @PJ_Glasso

do you know where I can download the driver you mentioned?

It was strange that I was able to use the webtool to flash TRMNL firmware then the firmware performed an auto firmware upgrade then it never comes back. When I tried again to flash the lower version firmware again the web tool just said preparing then timeout.

So I tried different cables, rebooted, tried the BOOT mode to flash the factory but doesn’t work.

I was wondering if it’s bricked but after searching, it’s said the esp won’t break as the ROM is not writable.

10

FYI the TRMNL unit is a S3… in case that helps

11

@cgwaltney
I used the trmnl official tool to flash a XIAO 7.5 eink display which is a esp32c3

12

umm… did you look at the link i provided above? what da?

13

Yes. The model in your link is esp32s3 while they have a model built with esp32c3. It’s called Xiao 7.5” ePaper panel. TRMNL has official bin for it too

14

fair enough… just know the C3 and the S3 are completly different hardware so the code would not be interchangable