HTCC-AB02A won't upload

Hi, I have two HTCC-AB02A. One works fine. The other started showing nonsense characters in the Arduino IDE Serial Monitor before becoming completely unresponsive. It does not upload sketches:

Initialising bootloader. Unhandled error: Timed out waiting for Bootloader response.

Note that the device normally goes into programming mode automatically, I don’t have to press the RST/USR buttons. The IDE’s Tools | Burn Bootloader menu option don’t do anything either:

Error while burning bootloader
java.lang.NullPointerException
	at cc.arduino.packages.uploaders.SerialUploader.burnBootloader(SerialUploader.java:329)
	at processing.app.Editor.lambda$handleBurnBootloader$61(Editor.java:2379)
	at java.lang.Thread.run(Thread.java:748)
Error while burning bootloader.

I’ve been using it with an ADXL345 accelerometer. Is this Cubecell dead? Is there a way to get the bootloader on there, if that’s the problem?

Device information (same for both boards, the working and non-working one):

BN: Unknown board
VID: 10C4
PID: EA60
SN: Upload any sketch to obtain it

Thanks!

I as having some issues with Arduino IDE 1.8.15 (the latest one) So I switched to the 2.0 Beta and had more success. Maybe worth a try.

Try to press and hold the user button to power on,or keep pressing USER after power-on, and release USER after pressing RST once.

hi, that didn’t help. is this device bricked? i haven’t even used it very long. is there no way to make it work again? I have one more, but i don’t want to use it until i know what to do with this one.

do the other cubecell devices (capsule, etc.) have the same problem? with a regular arduino, i’ve flashed easily 100 times without any problems. Even been able to play with the bootloader if i wanted to.

is the cubecell very fragile?

thanks!

Hi, is there anything that can be done with this non-responsive HTCC-AB02A? It returns the board info properly, but I cannot upload anything. Please help!

BN: Unknown board
VID: 10C4
PID: EA60
SN: Upload any sketch to obtain it