I'm a reseller of printers and I have several c5210 currently having this problem. After October update, the Epson c5210 can not be recovered.
I have access printer firmware update mode, re-update the firmware into the Chipless version, try to recover the chipless using the recovery code. But receive this error:
It is highly because the Epson new firmware has prevent chipless from being recovered/working. Can you update the firmware for c5210/c5290 please.