Present already?
Working back up the stack;
1. dev/pci/isakbd.fth loads dev/pckbd.fth and dev/i8042.fth
2. dev/pci/isaall.fth loads dev/pci/isakbd.fth
3. cpu/x86/pc/biosload/devices.fth loads dev/pci/isaall.fth
4. cpu/x86/pc/biosload/fw.bth loads cpu/x86/pc/biosload/devices.fth
5. fw.img is made from cpu/x86/pc/biosload/fw.bth
6. cpu/x86/pc/biosload/ofw.bth loads fw.img
6. ofwgrub.elf is made from cpu/x86/pc/biosload/ofw.bth
Might be worth adding some messages to the ISA driver start to debug.