Open Firmware is now *open*

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Jon's picture
Jon
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From browsing a /. article on the OLPC project, I found a link that SUN has released OpenFirmware when they released OpenSolaris. OLPC wants to use an OF payload to boot the OLPCs. That seems like a great idea. Now with an open code OF, couldn't some nice programmers write some updates for Apple hardware OF? There's some long standing bugs in the older OF ROMs, but they'd be a PITA to update. However, one might be able to add back in USB booting to the machines that dropped it, among other nice features. I wonder how much Apple IP there is in the OF used on PPC machines vs the actual licensed SUN code.

http://www.openbios.org

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madmax_2069's picture
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i hope someone could add G4 s

i hope someone could add G4 support to the Beige G3 computers. so it can see the correct info and addresses of the L2 cache and L1 cache. cause in OF there is only info for the 60? and G3 CPU's. when a G4 cpu is installed it will run at the correct speed but the L1 cache is only 16 x 16 bits and it should be 32 x 32. and it dont see any L2 cache cause its using info for the 60? series of CPU's that explains why cpu's from a Yikes G4 dont work properly in a Beige G3. if there was some way to take the proper info from the Yikes G4 OF and make a firmware update for the Beige G3 to it has the proper info for the G4 cpu's it would properly detect the G4 cpu and will work like it should without any cpu enabler software. heck that would be awesome if that could be done. i would love to see alot of updates to the OF on the Beige G3

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re: firmware

Confusion betweem firmware and OpenFirmware is common, they aren't the same thing. OF is used pre-boot, to define the hardware system parameters for whatever OS happens to use the machine. Pre-NewWorld Macs use a MacOS-based ROM, which provides a built-in set of basic MacOS routines for MacOS.

Pre-NewWorld Macs cannot have their ROMs updated, short of physical replacement, as it's hardwired onto a ROM SIMM (DIMM?) It's unlikely anyone will ever produce a G4-savvy ROM for any pre-NewWorld Mac.

new world

dan k

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madmax_2069's picture
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darn , but i was thinking of

darn , but i was thinking of the right thing tho on how if the info was there that the Beige G3 could fully use the G4 cpu without having to have software to enable the L2 cache. i know that manualy if you input the info in OF that it will work but will get removed once you reset pram or press the cuda. but i was hoping that there could be a way to get the info to saty ib even tho the pram got zapped . but of well it was a good shot. i hope somthing good could come from this going open

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why doesnt someone reverse en

why doesnt someone reverse engineer the rom simm from a beige. then sell new roms for $100? ive got a rev a rom tht ill donate for the cause

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Because you can buy a Quicksi

Because you can buy a Quicksilver G4 for under $100. Why spend that much money on a $20 computer to get it to match the abilities of a $40 computer?

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so what ive take on what was

so what ive take on what was said here is that the rom in the Beige G3 isnt flashable. i could be wrong but if it is. this could be done and allot can be fixed of bugs in the diffrent rom sets AKA like the rev a rom if you use OS 9 cant do slave master drive configs. and may fix a few PCI glitches as well. who knows if it can be but. it all boils down to if the rom can be flashed or not or if one can be made

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It also matters as to how muc

It also matters as to how much of the SUN code is in the Apple firmware. Note that SUN didn't release Apple Open Firmware. SUN released code for the Open Firmware spec, which in a SUN machine is called Open Boot PROM. THe main point of my post was that it is now possible to hack the code, as one doesn't need an expensive dev. license and an NDA to see how the code works. There's a lot of work to get anything fixed, but many of the legal implications just opened up.

The issue of ROM vs flash is that it takes either opening up the machine and plugging in a new ROM SIMM (many older Macs have them) or desoldering and replacing the chips on the board itself. It's much more non-trivial than reflashing. Of course, flashing can leave a dead board, too. At least with a ROM SIMM one could pull it back out and probably not have any damage tot he machine.

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Re: why doesnt someone reverse en

gobabushka wrote:

why doesnt someone reverse engineer the rom simm from a beige. then sell new roms for $100? ive got a rev a rom tht ill donate for the cause

Already been done. The price on Ebay is down under $20 for a Rev. C ROM, so generally, it isn't worth producing them. The circuit boards run about $6 - $7 in 200 unit production lots and the chips (four Flash chips) are about $2 each. So there's $14 - $15 in materials before considering time and assembly costs. Not to mention the copyright issue. I.e. if Apple takes notice they have a pack of attack lawyers.

However, such a project does lend itself to hacking the Apple ROM code in the Beige G3. For example, if someone wrote modified ROM code for the Apple Beige G3, that code could be programmed into Flash chips, the chips attached to a circuit board, and voila, modified Beige G3 ROM.

If some skilled programmer is serious about hacking the ROM code contact me (trag@io.com) and I'll see what I can do about putting your code on hardware. Additionally, I'm happy to provide the pinout for the ROM module if anyone wants to see it. It might take me a while to type it in.

But it isn't difficult to reverse engineer. Get an existing ROM module. Determine which chips were used on the board. Get a data sheet for those chips. Use an ohm meter to see which DIMM pins connect to which pins on the chips.

To make things even easier...The ROM chips on the Apple Beige G3 ROM are the same as or the equivalent of the Sharp LH53BV16900 or the Macronix MX23L1622. They're weird as can be because they are 32 bits wide. You won't find any currently shipping flash chips that are 32 bits wide. That's why any new product needs to use four chips which are 16 bits wide instead of two 32 bit wide chips.

Some odd details... Pin 122 is grounded in Power Computing (PCC) modules. Grounding pin 122 in the Beige G3 ROM disables support for 256 MB memory modules. The Biege G3 needs 90 ns or faster flash memory. 120 ns does not work. 100 ns might. However, x500 machines seem to work okay with 120ns.

Additionally, the x500 and x600 series of PCI Powermacs use exactly the same ROM module with slight modification. The slight mod is that the power supply pins are in different locations (5V on x500, 3.3V on Beige) and pin 116 needs to be tied to power in the x500/x600 so that when the ROM is installed it will disable the motherboard ROM.

So the same ROM module (with different Powr supply pins enabled; user installable 0 ohm resistors) can be used to, e.g., put the Kansas ROM in a 9500, thus removing the Speculative Processing issue with G3 processors.


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i do know the rev b and rev c

i do know the rev b and rev c roms are almost identical to each other but there are some pci cardds out there that is not compatable with the rev c rom. both my AIO's have a rev b rom. and i have i think a rev a chip laying around but the rev a rom had its fare share of bugs and its just going to lay there collecting dust cause both my Beige G3's are rev b.

if people are into this that would be great cause it would be sad to see this opportunity die off. but most likely will cause the amount of money one would have to invest into it. but i do hope that this could happen

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Re: Because you can buy a Quicksi

moosemanmoo wrote:

Because you can buy a Quicksilver G4 for under $100. Why spend that much money on a $20 computer to get it to match the abilities of a $40 computer?

I disagree with that. Prices are much higher. I troll craiglist and I haven't seen that at all. Prices on a G4 450 are a firm $200 never mind higher processor speeds.

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yea since the switch to intel

yea since the switch to intel the ppc mac's have grown in popularity and people are in like a Mac buying spree and the sellers see this and jack up the price. this could be somthing for money gains or just for kicks for proof of concept and there is allot of people out there that love there Beige G3's and could be a market for it. selling it on ebay or what have you could see profit but also could land nowhere. who knows. all i know if somthing like this was made i would buy one

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