I accidentally uploaded the WR21 firmware to a WR31. Is there any way to recover the modem?
Yes, there are multiple ways to recover the WR31 depending on how broken it is.
If you have not corrupted the bootloader then a simple flashwrite will work to fix it.
https://www.digi.com/support/knowledge-base/how-to-upgrade-the-firmware-on-a-digi-transpor-(2)
If you have killed the bootloader it is a much trickier process but can be recovered too.
Nicholas Wilson
Your IoT