It seems, something is broken with the Floppy Disk support. Example: I am no more able to boot UCSD p-System disks. P-Code card is on. Will check also other disks (Assembler/Basic) and ti99_xx driver.
OK, it seems only boot disk problem exist, if the P-Code card is activated. Without the P-Code card, I can boot disks.
The problem not exist with the official MESS 0.134 release.