> The problem is currently OpenBIOS won't work on a bare metal, since 
> it's tightly coupled with qemu. So, PROM size at this point is a 
> purely academical question. 

I'm involved in a project where OpenBIOS for Sparc32 is actually used on bare metal (in a FPGA). 
OpenBIOS is installed in a 16MB NOR FLASH. 

There are a few QEMU dependencies and some small issues which don't appear in QEMU (for example, 
 the MMU activation sequence does not work IRL, there is a small bug in wuf.S ...). 

Regards, and thank you all for your hard work ! 
 
Olivier