In my search I found this method for "unbricking" a PRS-500, so I wonder if there is a similar way for the PRS-T1?
Recovering From Catastrophic Failure (Unbricking)
If you manage to completely brick the device to where it cannot boot at all (remains at "Starting up..." page indefinitely), you will need to do the following to recover to the factory flash image.
1. Charge the device overnight to make sure it has enough power for the recovery process.
2. Use a paper clip or pin to depress the reset button in the small hole on the back of the unit. Turn the unit on.
3. Wait until the "Starting up..." page is displayed for a few seconds and you see the orange LED blinking. Just count like 3 to 4 sec. from the moment you see the LED blinking.
4. Repeat steps 2 and 3 ten times.
5. On the tenth reset let the Reader boot and after a few minutes the message "Firmware update is not finished correctly. Please execute firmware update again." will be displayed.
6. Connect the USB cable and the device will automatically go into recovery ("Updating firmware now...") mode.
7. Flash the device with the original PRS500 updater.
I found this here:
https://wiki.mobileread.com/wiki/Sony_Reader_hack
I am trying this with a PRS-T1 right now....