exxos's Atari, Amiga & retro forum

I've just opened up my Mega ST4 to see what my options were to upgrade the TOS version (currently 1.02)...mine currently has the two TOS ROMs fitted & the other 4 ROM sites are empty (no sockets present, holes appear to be free of solder).

I really want to upgrade it to TOS 1.04 as a minimum (it has a Megafile 60 with it & so all those bug fixes would make sense) but I'm not sure if my best/easiest option is to fit 6x ROMs (and swap some solder links?) or to just replace the 2x ROMs (and if so, what parts do I need)?

My main use will be MIDI s/w (Cubase/Notator & possibly Logic) - I have the various dongles and Midex+/Unitor/Unitor 2 & even a Combiner so that might limit some of the options.

Any suggestions will be most welcome - I'm working on saving up some funds to order some goodies & feed Harry (the wish list is way beyond my available funds sadly) but I do have a programmer as a short-term solution.

Morning Jez,

The easiest option is to fit one of exxos's rom boards in the place of the two Roms, don't forget to order the eprom as well :D

It depends if your CPU is socketed but you could also add a booster fairly quickly if it is, or even get involved with the IDE booster testing which has the ROM switcher built in.

Hi Phil,
Yes that's one option I'm considering, funds being the biggest issue preventing me this month. :cry:
If the 2 chip UK TOS 1.04 were in stock then that would be the simplest way to go, but alas there are none ATM. :cry:

68k isn't socketed sadly and I'm not yet confident enough to risk adding one, need to practice on a faulty STFM first. :roll:

I like the sound of the IDE board & also the ROM + RTC option...but both are more appropriate to one of my STF/STFMs.

I will see if I can get some blank PROMs or something.

The schematics will show the jumper settings from 2 chip to 6 chip.

TOS
https://www.exxosforum.co.uk/forum/viewt ... f=25&t=116


ROMSPLIT ( can't find it in our software section )
http://atari.8bitchip.info/ROMSPLIT.ZIP


SCHEMATICS
https://www.exxosforum.co.uk/forum/viewt ... f=31&t=100

TOS104 will almost never be in stock in my store. Only source for them is old machines, and I rarley buy any these days, and the boards I do almost never have 104. Its why I make the various ROM adapter boards.