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Hi Mike G,

Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!!

Mike (C)

Quote

> Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this.

Well, basically it is the same principle as in the case of replacing ROM by an EPROM in SMS cartridges.
Read most of the posts below and you'll get the base.
Pinout is probably different, but that's something he will quickly post here if you are interested ^_^

Quote

> The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!!

Don't get yourself wrong, you won't hear FM musics on your European/US system with the Japanese BIOS ;-)
The point if you replace your BIOS is that:
- you will be able to play Japanese MyCards games (including SG-1000 ones)
- with an adapter (the one I talked you about by e-mail), you will be able to play Japanese Cartridges (SG-1000, SMS, etc..)

Quote

> Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!!

All you really need to do is desolder the 28 pin BIOS chip (this is the chip marked MPR-xxxxx where xxxxx is a five digit number), and replace it with a socket into which you can plug an 8K EPROM containing the Japanese BIOS. The pinout is much the same, so you don't need to cut any traces or make wire links.

Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them.

Desoldering the BIOS chip is the trickiest part of the procedure. Use the finest gauge desolder braid you can find, don't use a desolder pump (the board traces are easily damaged). SMS boards have plated through holes, so you may have to desolder each pin twice - i.e. on both the top side and the underside of the board.

One thing worth mentioning about the Japanese BIOS is that it won't boot your SMS in Japanese mode (i.e. games like Aztec Adventure don't have the Mark III bumpers and Japanese titles). I don't know what determines the language mode of the SMS, and I don't suppose I will until I get a Japanese SMS or Mark III to take apart :)

Mike G

Quote

> One thing worth mentioning about the Japanese BIOS is that it won't boot your SMS in Japanese mode (i.e. games like Aztec Adventure don't have the Mark III bumpers and Japanese titles). I don't know what determines the language mode of the SMS, and I don't suppose I will until I get a Japanese SMS or Mark III to take apart :)

The country is determined by the software by an hardware port, which is unrelated to the BIOS.
Electronically speaking it is probable that a simple modification on a machine could change the country, but I don't now how to yet.

Quote

> > Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!!

???is it? it's got kind of a neat default screen, but it doesn't do much beyond that (actually it's benefits are in what it doesn't do: checksum tests and other verification)

Quote

>

> Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them.

That reminds me of an idea that occured to me about a week ago:
Until we get a proper devcart built, it would be handy to be able to cut down on the number of erasures necessary in development. It occured to me that you connect the high address pins (a17-a19) of a 1 megabyte eprom to an 8-position dip switch, and get 8 128kbyte selectable 'slots' on a single eprom. That way you would only need to erase it every 8 burns, and could review your history. (plus you could put 8 1 mega games on a single rom for playing pleasure, but then I'm not endorsing that, nudge nudge).
I don't know what else is involved though...

Quote

> Desoldering the BIOS chip is the trickiest part of the procedure. Use the finest gauge desolder braid you can find, don't use a desolder pump (the board traces are easily damaged). SMS boards have plated through holes, so you may have to desolder each pin twice - i.e. on both the top side and the underside of the board.

Mike, could you give me a brief rundown on the process of replacing a rom on an sms cart with a socket and an eprom? Also, as for using a desoldering braid, any advice on which kind to get (width as well as other options like 'no clean', antistatic, rosin/no rosin...).
I think I'll give it a test run on my captain silver cart. Damnable crappy game.

Quote

> > Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them.

> That reminds me of an idea that occured to me about a week ago:
> Until we get a proper devcart built, it would be handy to be able to cut down on the number of erasures necessary in development. It occured to me that you connect the high address pins (a17-a19) of a 1 megabyte eprom to an 8-position dip switch, and get 8 128kbyte selectable 'slots' on a single eprom. That way you would only need to erase it every 8 burns, and could review your history. (plus you could put 8 1 mega games on a single rom for playing pleasure, but then I'm not endorsing that, nudge nudge).
> I don't know what else is involved though...

It's a damned good idea, and it wouldn't be too hard to modify the EPROMr2 source code to write a 1 MByte EPROM in 128k segments. I'll take a look.

Quote

> Mike, could you give me a brief rundown on the process of replacing a rom on an sms cart with a socket and an eprom? Also, as for using a desoldering braid, any advice on which kind to get (width as well as other options like 'no clean', antistatic, rosin/no rosin...).

I've written a short article on this procedure for 1 Mega carts with the 315-5208. The 315-5235 and 5365 based carts are a lot more straightforward to do, but the stuff about desoldering still applies.

As for the desolder braid, 1.5mm width (AA gauge) is about right. The rosin impregnated stuff is what you want - I think the non-rosin stuff is for mopping up flux, not solder. (Hence "clean" versus "no clean" - "no clean" is the stuff to get.)

Mike

315-5208 Article

Author	Message
Mike C Joined: 10 Oct 1999 Posts: 211 Location: Lebanon, New Hampshire, USA	To Mike G - Replacing BIOSes?!? Posted: Sun Aug 06, 2000 2:54 am
	Hi Mike G, Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!! Mike (C)

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	Posted: Sun Aug 06, 2000 9:34 am
	Quote > Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. Well, basically it is the same principle as in the case of replacing ROM by an EPROM in SMS cartridges. Read most of the posts below and you'll get the base. Pinout is probably different, but that's something he will quickly post here if you are interested ^_^ Quote > The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!! Don't get yourself wrong, you won't hear FM musics on your European/US system with the Japanese BIOS ;-) The point if you replace your BIOS is that: - you will be able to play Japanese MyCards games (including SG-1000 ones) - with an adapter (the one I talked you about by e-mail), you will be able to play Japanese Cartridges (SG-1000, SMS, etc..)

Mike G Joined: 21 Apr 2000 Posts: 598 Location: Newcastle upon Tyne, England	Posted: Sun Aug 06, 2000 11:17 am
	Quote > Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!! All you really need to do is desolder the 28 pin BIOS chip (this is the chip marked MPR-xxxxx where xxxxx is a five digit number), and replace it with a socket into which you can plug an 8K EPROM containing the Japanese BIOS. The pinout is much the same, so you don't need to cut any traces or make wire links. Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them. Desoldering the BIOS chip is the trickiest part of the procedure. Use the finest gauge desolder braid you can find, don't use a desolder pump (the board traces are easily damaged). SMS boards have plated through holes, so you may have to desolder each pin twice - i.e. on both the top side and the underside of the board. One thing worth mentioning about the Japanese BIOS is that it won't boot your SMS in Japanese mode (i.e. games like Aztec Adventure don't have the Mark III bumpers and Japanese titles). I don't know what determines the language mode of the SMS, and I don't suppose I will until I get a Japanese SMS or Mark III to take apart :) Mike G

Zoop Joined: 24 Jun 1999 Posts: 1732 Location: Paris, France	Posted: Sun Aug 06, 2000 12:01 pm
	Quote > One thing worth mentioning about the Japanese BIOS is that it won't boot your SMS in Japanese mode (i.e. games like Aztec Adventure don't have the Mark III bumpers and Japanese titles). I don't know what determines the language mode of the SMS, and I don't suppose I will until I get a Japanese SMS or Mark III to take apart :) The country is determined by the software by an hardware port, which is unrelated to the BIOS. Electronically speaking it is probable that a simple modification on a machine could change the country, but I don't now how to yet.

Heliophobe Site Admin Joined: 25 Oct 1999 Posts: 2029 Location: Monterey, California	Re: To Mike G - Replacing BIOSes?!? (yippee! -another- "Mike" on S8-Dev) Posted: Sun Aug 06, 2000 9:46 pm
	Quote > > Thanks for all of your helpful answers regarding my Japanese PBC. I was very much intrigued by your mention of replacing your SMS' BIOS (I had seen your earlier posting here). Rather than bog down the smslist with a technical discussion, I was wondering if you might tell me how you got around to doing this. The Japanese BIOS is the coolest console BIOS I've ever seen!!!!!! ???is it? it's got kind of a neat default screen, but it doesn't do much beyond that (actually it's benefits are in what it doesn't do: checksum tests and other verification) Quote > > Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them. That reminds me of an idea that occured to me about a week ago: Until we get a proper devcart built, it would be handy to be able to cut down on the number of erasures necessary in development. It occured to me that you connect the high address pins (a17-a19) of a 1 megabyte eprom to an 8-position dip switch, and get 8 128kbyte selectable 'slots' on a single eprom. That way you would only need to erase it every 8 burns, and could review your history. (plus you could put 8 1 mega games on a single rom for playing pleasure, but then I'm not endorsing that, nudge nudge). I don't know what else is involved though... Quote > Desoldering the BIOS chip is the trickiest part of the procedure. Use the finest gauge desolder braid you can find, don't use a desolder pump (the board traces are easily damaged). SMS boards have plated through holes, so you may have to desolder each pin twice - i.e. on both the top side and the underside of the board. Mike, could you give me a brief rundown on the process of replacing a rom on an sms cart with a socket and an eprom? Also, as for using a desoldering braid, any advice on which kind to get (width as well as other options like 'no clean', antistatic, rosin/no rosin...). I think I'll give it a test run on my captain silver cart. Damnable crappy game.

Mike G Joined: 21 Apr 2000 Posts: 598 Location: Newcastle upon Tyne, England	Re: To Mike G - Replacing BIOSes?!? (yippee! -another- "Mike" on S8-Dev) Posted: Mon Aug 07, 2000 10:33 pm
	Quote > > Another option is to blow both Japanese and US BIOSes onto a single 16k chip, with a switch attached to the A13 line (pin 26) to flick between them. > That reminds me of an idea that occured to me about a week ago: > Until we get a proper devcart built, it would be handy to be able to cut down on the number of erasures necessary in development. It occured to me that you connect the high address pins (a17-a19) of a 1 megabyte eprom to an 8-position dip switch, and get 8 128kbyte selectable 'slots' on a single eprom. That way you would only need to erase it every 8 burns, and could review your history. (plus you could put 8 1 mega games on a single rom for playing pleasure, but then I'm not endorsing that, nudge nudge). > I don't know what else is involved though... It's a damned good idea, and it wouldn't be too hard to modify the EPROMr2 source code to write a 1 MByte EPROM in 128k segments. I'll take a look. Quote > Mike, could you give me a brief rundown on the process of replacing a rom on an sms cart with a socket and an eprom? Also, as for using a desoldering braid, any advice on which kind to get (width as well as other options like 'no clean', antistatic, rosin/no rosin...). I've written a short article on this procedure for 1 Mega carts with the 315-5208. The 315-5235 and 5365 based carts are a lot more straightforward to do, but the stuff about desoldering still applies. As for the desolder braid, 1.5mm width (AA gauge) is about right. The rosin impregnated stuff is what you want - I think the non-rosin stuff is for mopping up flux, not solder. (Hence "clean" versus "no clean" - "no clean" is the stuff to get.) Mike 315-5208 Article

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