@Amiganew:
from your last post... seems that you found *ROMEN
I found the A500 schematics... but I don't remember where, Google for them (A500 schematics, can do). If you don't find them, I can send you them.
Within the pics are the pinouts of flash and Amiga ROM chips, *OE in the AMIGA ROM is the *ROMEN signal generated by the Gary chip.
*** Note: *OE, !OE and /OE mean the same, a low active signal.
*** NOTE: *OVL is generated by one of the CIAs to map temporarly the ROM at 0x00000 so the 68k can find the vector table, is later negated during the boot process.
There is floating a dissasembled kickrom that you can read, clarifies a couple of things. I think is in aminet.
Sorry if you already knew all this.
(If you don't understand something, I can do my best and translate it to Deutsch).
The board can be done with the wire-up method, or you can draw a borad in some pcb editing software and later transfer it to a real pcb with the UV method or simple hand drawing, whatever you think is better (I'd recommend the later method for simplicity and better results).
Have fun, and don't forget to post pics and results !