Fatal disk errors
Hook #F323 ( Double indirection )
Hook #F273 ( 3 bytes ) Exit to #471A to DISKROM ( Registers not stored )
A - Drive
C - Error code:
X x x x X X X X
|       | | | |
|       | | | +------------ 1 - Writing / 0 - Reading
|       | | +----- 0 1 1 #
|       | +------- 0 0 0 #- Disk error (other)
|       +--------- 0 0 1 #
|                  | | +--- Unsupported media
|                  | +----- Not ready
|                  +------- Write protect
+-------------------------- 1 - Bad FAT

Return status
#F323 - C
#F273 - A
0 - Ignore
1 - Retry
2 - Abort

#F1E6 - Address of ABORT