As one of the instruction manuals somewhere on this website indicates, the ABS brain loses its memory if deprived of power for an extended time. I installed a used ABS brain to replace my faulty one, the light wouldn't stop blinking, I reset it following the somewhat arcane process of jumper wire from middle pin on the blue plug to ground, press ABS button, hold it, turn key on but don't start bike, wait 20 seconds, turn off, disconnect everything, go for a ride and see if the light goes out.
It's a mini-celebration when it works. Sometimes the phase of the moon may be wrong or I was not holding my grimace just quite right and I'd have to repeat.