M200 don't update Firmware when turn on, model list is normal.
Zer, in order to update firmware you have to transfer "update.bin" file onto SD card. It has to be the only file on the card. It's very important. Otherwise the firmware won't install.
Moreover, insert the card when the printer is off. Then launch the M200 and wait a couple of seconds. Firmware should be installed quickly.
Yes, "update.bin" file is the only file on the card, didn't install firmware when launch. Other M200 can install using same SD card, only one M200 can't.
Please format the card using FAT 32 and try again. If that does not help too, get a different card.
Is the problematic M200 a bit older than the one you can update normally without any issue?