Changes
1 byte 'N' (defined by FDC format command)
2 bytes CRC (stored big endian, i.e. high 8 bits, then low 8 bits).
Gap 2 (22 bytes of 4E)
The CRC for the ID field is computed from the 3 bytes of A1, the 1 byte FE, C,H,R and N. When verifying include the CRC and if the result is 0, then the CRC is correct.
Gap 4 ('n' bytes of 4E all the way to the end of the track).
NOTE: A1/C2 are the only MFM-words which have a missing clock. All the others are written like normal data bytes.
