Date   : Thu, 22 Jan 2004 11:36:47 +0000
From   : "Nick B." <nick@...>
Subject: Master 128 MOS roms (was Re: Host adapter Issue D)

On Wed, 21 Jan 2004 23:04:15 +0000, "Mike Tomlinson"
<mike@...> said:
> In article <Pine.LNX.4.50.0401212118100.2821-100000@...
> g>, Andrew Benham <adsb@...> writes
> 
> >Here's a quick plug for my fix:
> >
> >    http://www.adsb.co.uk/bbc/bbc_master.html
> 
> Very nicely documented, especially the adapter to put a 1Mbit EPROM into
> the MOS's 28 pin socket - thank you.  Was MOS 3.50 an official Acorn
> release, and is it available for download anywhere?

I recently installed MOS 3.50 in one of my M128 machines, I found the ROM
image somewhere out there. I couldn't get hold of a 32-pine wire wrap
socket so I built up an adaptor board using veroboard, a 32-pin socket
and header pins.
The EPROM I used was actually an EEPROM salvaged from a scrap pentium
motherboard which I can re-program quickly without having to go through
the UV erase process. At some point I might try to apply the K2k fixes
too. 
The only problem I encountered was reverting back to MOS 3.20 rendered
the machine unusable (Just a continuous tone) until I cleared the CMOS by
removing the backup battery.
Thanks to Pete for FinMOS, I will try that at some point too.
-- 
Nick B.