basically you trashed the firmware on the printer.
your only hope of fixing it is if you can hook it up with a usb cable and re run the firmware update.
it may not work as updating the firmware requires that the firmware be working well enough to at least start the firmware update.
to be honest my best advice would be to spend half an hour trying to do the update again through a usb cable.
if it wont work, toss the printer in the garbage ( or call epson and see if its under warranty or if you can bully them enough about their own firmware update screwing up the printer to get it replaced)
and buy a new one if epson wont help you.
they go for 60 to 80 bucks. Its not worth repairing it or even spending a lot of time trying to fix it.
You can call epson at
1 (800) 444‑1527
M‑F 6am‑ 8pm PT
S 7am‑ 4pm PT
i hope that is helpful. I try to avoid doing firmware updates unless the device is having issues that the update will fix. Because if it fails you get a large expensive paperweight more often than not.