Command $1C (SEEK_WITH_VERIFY) does not work as intended.
The diagnostic routines (RX50 DIAG.DISK) appear to use it extensively for READ and WRITE tests. Where is the bug?
https://dl.dropboxusercontent.com/u/37819653/BANNISTER/SEEK_WITH_VERIFY_FAILS_1.jpghttps://dl.dropboxusercontent.com/u/37819653/BANNISTER/SEEK_WITH_VERIFY_FAILS_2.jpgHint: there is a disassembly of the main BIOS routines for the Z80 at
https://github.com/shattered/retro-bios/tree/master/dec-rainbow100bSearch for WRITE and 1Ch.