Whoops.. I think I accidentally e-mailed Tom this reply vs posting it
to the group..

I was able to do some experimenting tonight..

Dumped the ROMs from my 128EX v6.0 and regular 128 v6.0 - they were
identical.

However, took Tom's 6.1 EX/2 ROM and loaded it into one of my junker
128's (Non-EX), and maybe surprisingly, it booted up and worked fine.
I was even able to access the EX/2 control panel (with time date
settings, etc - of course they didn't stick, though) on the regular
128.

So, looks like the 128 and 128EX ROMs are the same, but the EX/2 is
different.

An interesting anomaly - the pitch of the "beep" on the Laser 128
using the EX/2 ROM changed along with the speed setting (normal,
medium, fast) in the control panel and by doing the ctrl-(1..3)-reset
key combination.. Of course, the system's speed didn't actually
change.  Interesting, though, because I always thought the EX and EX/
2's 'beep pitch' change according to speed was actually due to the CPU
speed. Looks like it's artificial.
--- SBBSecho 2.12-Win32