Thanks for the hints, will check the TO debugger command. handle_packet is not called, it stops before that. filesys_diagnetry is run.
The differences I see from the UAE side are (some additional logging added, red color is missing from the nonworking version):
Code:
...
Memory map after autoconfig:
00000000 2048K/4 = 512K Chip memory
00200000 8192K/0 = 8192K <none>
00A00000 2048K/0 = 2048K CIA
00C00000 512K/1 = 512K Slow memory
00C80000 1024K/0 = 1024K Custom chipset
00D80000 256K/0 = 256K <none>
00DC0000 64K/0 = 64K Battery backed up clock (MSM6242B)
00DD0000 64K/0 = 64K <none>
00DE0000 128K/0 = 128K Custom chipset
00E00000 512K/1 = 512K Kickstart ROM (F6290043)
00E80000 64K/0 = 64K <none>
00E90000 64K/0 = 64K Filesystem autoconfig
00E90000 64K/1 = 64K Filesystem autoconfig (64K/1 instead of 64K/0)
00EA0000 384K/0 = 384K <none>
00F00000 64K/1 = 64K UAE Boot ROM
00F10000 448K/0 = 448K <none>
00F80000 512K/1 = 512K Kickstart ROM (F6290043)
TRAP: filesys_diagentry
TRAP: mousehack_done
mousehack_done mode = 17
TRAP: mousehack_done
mousehack_done mode = 18
TRAP: mousehack_done
mousehack_done mode = 4
PAL mode V=50.0000Hz H=15625.0881Hz (227x312+1) IDX=10 (PAL) D=0 RTG=0/0
TRAP: exter_int_helper
TRAP: exter_int_helper
TRAP: exter_int_helper
Display Size: 640x400 Offset: 74x36
TRAP: filesys_dev_storeinfo
Mounting uaehf.device 0 (0):
FS: mounted virtual unit DH0 (./.)
So it looks like filesys.asm isn't triggering the exter_int_helper trap. Could be a problem with the setup there. Also, the missing mousehack_done mode = 17 (clipboard integration) is suspicious, but on the other hand, filesys.asm was also updated as part of the changes, so that might be normal. The next step might be for me to compile a special debug version of WinUAE (with the same features enabled as in FS-UAE), and try to run a detailed comparison of the boot process.