The firmware will need to be reset to 30 amps.
If you have functional software on the SD card try unlobotimizing and using the maintenance screen to reset to 30.
If SD card is corrupted you'll need to generate new SD card.
Info on that is later in the thread.
My SD card corrupted and I have been meaning to replace but haven't found the time or enthusiasm to bother.
But as you said a dumb Blink is probably a better Blink anyway.
But the only way I know to reset the firmware is with functional software and maintenance screen.