Back Porting the Classic ROM to the SE

[Phipli]

Hey folks, what if anything is stopping you flash the Classic ROM to a Hi and Lo chip for the SE?

This would gain you a ROM disk, and perhaps some bug fixes, not sure. As well as being a FDHD compatible ROM.

Anyone got thoughts on this?

 

[cheesestraws]

No idea! Try it and see what breaks...

 

[Phipli]

No idea! Try it and see what breaks...

As long as it isn't me

 

[Snial]

Hey folks, what if anything is stopping you flash the Classic ROM to a Hi and Lo chip for the SE?

This would gain you a ROM disk, and perhaps some bug fixes, not sure. As well as being a FDHD compatible ROM.

Anyone got thoughts on this?

View attachment 65836

Don't you need SWIM for FDHD?

-cheers from Julz

 

[Phipli]

Don't you need SWIM for FDHD?

-cheers from Julz

Yes, but also an updated ROM. You need both.

 

[Snial]

Yes, but also an updated ROM. You need both.

Lightbulb moment: aaah, I didn't realise all SEs had SWIM, I just thought the FDHD versions did!

 

[cheesestraws]

Lightbulb moment: aaah, I didn't realise all SEs had SWIM, I just thought the FDHD versions did!

They don't. 800K SEs have an IWM and matching ROM. FDHD SEs have a SWIM and matching ROM. The upgrade involved switching out both the floppy controller and the ROMs.

 

[LaPorta]

Gonna swap the ROMs in and see what happens?

 

[Phipli]

Gonna swap the ROMs in and see what happens?

Takes a bit more than that - they're not the same shape.

 

[LaPorta]

Hadn't even looked at them. Guess that would matter slightly, hmm? .

 

[Snial]

They don't. 800K SEs have an IWM and matching ROM. FDHD SEs have a SWIM and matching ROM. The upgrade involved switching out both the floppy controller and the ROMs.

OK, so what @Phipli means is that you take an SE FDHD and replace it with a Classic ROM as it defo won't work with the older SEs.

 

[LaPorta]

OK, so what @Phipli means is that you take an SE FDHD and replace it with a Classic ROM as it defo won't work with the older SEs.

...unless you also put a SWIM in the SE!

 

[Phipli]

...unless you also put a SWIM in the SE!

This really, but also...

OK, so what @Phipli means is that you take an SE FDHD and replace it with a Classic ROM as it defo won't work with the older SEs.

I'm not sure that you can't just use the newer ROM with an IWM and use an 800k drive.

But SWIM compatibility isn't really what I'm trying to understand, given that is unlikely to be any different to SE vs. SE FDHD... It's a more general, can you boot an SE from the Classic ROM, to gain the ROM disk.

 

[Snial]

This really, but also...


I'm not sure that you can't just use the newer ROM with an IWM and use an 800k drive.

But SWIM compatibility isn't really what I'm trying to understand, given that is unlikely to be any different to SE vs. SE FDHD... It's a more general, can you boot an SE from the Classic ROM, to gain the ROM disk.

OK. The reason I'm interested in this thread, is because I actually do have an SE (one with a broken flyback), giving it a Classic ROM sounds like fun (well, when the flyback can be fixed ;-) ) !

 

[LaPorta]

I think it’s a great experiment. I’d totally get some Classic ROM copies for my SE.

 

[ymk]

I remember problems swapping the BBU between SE and FDHD.

 

[Scott Baret]

Or you could just go the lazy route, put the contents of the Classic's ROM disk on a floppy, and use it to boot the Mac. It's 6.0.3, so it will work.

Also, does anyone know the story behind the funky Brightness control panel on the ROM disk? It's a vertical slider and the sun icon is thinner than usual...was it a beta version?

 

[dochilli]

As far as I know, the SE has a 256 kB ROM am the Classic a 512 kB. May be this is a problem?
For the SE there is a adapter pcb to use Epromms.

Macintosh SE EEPROM to ROM adapter

So, you have a Mac SE, or you're building up a Mac SE reloaded board using damaged donor that might have bad ROM chips (corroded legs, dead chip etc). Well through the magic of the internet I can bring you this, an adapter that replaces the stock Toshiba TC531000 mask ROMs with any 27C010's...

68kmla.org

 

[Phipli]

As far as I know, the SE has a 256 kB ROM am the Classic a 512 kB. May be this is a problem?
For the SE there is a adapter pcb to use Epromms.

Macintosh SE EEPROM to ROM adapter

So, you have a Mac SE, or you're building up a Mac SE reloaded board using damaged donor that might have bad ROM chips (corroded legs, dead chip etc). Well through the magic of the internet I can bring you this, an adapter that replaces the stock Toshiba TC531000 mask ROMs with any 27C010's...

68kmla.org

It could be, it depends if they ran an extra address line in the classic (versus the SE), and if they changed the memory map. I don't know enough about the Classic. This was actually what I started this thread to find out.

I feel like I half remember someone saying you couldn't put a bigger ROM in the SE. I'll have a look at the schematic.

 

[bigmessowires]

20 posts and nobody has tried jamming the Classic ROMs in there yet? If I had an SE, I'd try it. Maybe you could also test it with MAME.