iMX6ULL recovery: no RNDIS when config block is lost


I don’t know what broke flash. Colleague saw boot loop on console and then suddenly nothing, no logs or anything else.
I put Colibri into Iris board, put recovery jumper, connected to USB and run recovery-windows.bat. To my surprise RNDIS connection didn’t appear. I retried, no RNDIS again. Had to connect ethernet cable and configure IP from serial console. When VNC connected, Tezi UI said config block is lost. I think lost config block caused no RNDIS. At least on Linux BSP’s serial number is used to configure USB. I think missing serial leads to Tezi RNDIS failure. Could you fix this please, I mean only Tezi and Tezi recovery. It would be nice if RNDIS and fixed IP over USB connection would be available even in case config block is lost.

Thank you

Dear @Edward,

Thank you for writing to Toradex Community!

This issue you are currently facing is a known issue. If you use the RNDIS Interface, it is not possible yet to connect using VNC in case of missing/corrupt config block, since the Interface is not present in this case. We will try to correct this in the future.
Should you have a working u-Boot, you can use this to create the Config Block ( Command: cfgblock create).

There is a similar ticket in the community, which maybe helpful for you:

Hope this helps!

Best Regards,

Hi Janani,

Thanks for your reply.
I didn’t know it’s known, though I tried looking for something like this before posting.
U-boot isn’t necessary to recreate Config Block. After connecting over RS232 and configuring IP (DHCP client doesn’t work as well when config block is lost) and connecting to Tezi over LAN and VNC, Tezi UI asked to enter SN and model name and recreated config block, as well allowed to flash everything without reboot. So recovery is very easy with USB and boot jumper. The only missing piece is RNDIS and thus the need for extra time to make RS232 and ethernet connection, configure IP address.


Hello @Edward ,

I’m not entirely sure but am I right your solution is to flash the config block via Ethernet. Thanks a lot for your feedback!

Best Regards,