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owossoborn in ibookmod

1024x768 without going into open firmware

Hey! I see you had the forum posting for the 1024x768 clamshell hack closed at macnn.com. Glad to see you've persisted the info here.

I was researching something unrelated and saw that the method used to trick OSX with that process reminded me of this project. This new process doesn't give us any more features than we've already uncovered, but it does make implementing the old process MUCH easier. In fact, you don't even have to go into open firmware to do it.

As you recall, we were programming the nvramrc area with commands to trick OSX into thinking we had a different card/display installed, thus allowing 1024x768 resolution. I found that typing those nvramrc commands into the boot-command variable achieved the same result. There are only a few open firmware variables available to change from within OSX, luckily, boot-command is one of them.

1) reboot your clamshell holding down opt+cmd+p+r to reset open firmware and erase the nvramrc method.
2) boot into osx (I have osx on an external fw drive. Since we just reset OF, the boot-device is reset as well. So you may have to hold down the opt key during boot to allow the selection of the proper drive/partition to load osx.)
3) open up teminal and type the following (hitting enter at the end of each line):
sudo nvram boot-command='dev /
2 encode-int " display-family" property

*edit: I just realized that I'm using 2 and have 1024x768, not 1152x768. See my longer code post below in case the extra variables are why.

4) type in your password and then 'sudo reboot' (without quotes) to reboot
*if you forgot to add mac-boot to the end of it, then when rebooting, open firmware will open up and leave you at the blinking cursor. If that happens, simply type mac-boot and hit return in open firmware to continue on to booting osx. Once in osx, rerun the above command carefully to set it properly.

You should now have the same 1024x768 resolution enjoyed by the whole OF dance of the past. Anytime you want to change things, like for watching a dvd etc., simply keep the above in a text file where you can easily get to it. Open the text file, change the 3 to 2 or vice-versa, then copy/paste it into terminal and reboot. MUCH simpler than playing around with open firmware. I'm sure there's a way to turn this into a clickable apple script so you can just double-click on an icon to change what's entered into the boot-command variable, including automatic rebooting.

I've gone further and played around with changing the card vendorID/deviceID with success and intend on someday finding the elusive holy grail settings. :) I'm sure I can even change the machine model OSX sees from PowerBook2,2 to PowerBook 4,1. If anyone is interested in any of those other paths of frustration...er, I mean fun; if the subsystem-vendor-id and subsystem-id are 0 and the name variable is missing, OSX will go off the vendor-id and device-id only to figure out what the video card is. However, if I omit the name variable, OSX won't boot, so I changed it to what my machine 'thought' the card was whenever I was in holy-grail mode, ATY,RageM3p29s. I haven't touched this machine for a long time, and I'm sure I had changed/removed/bastardized some of the original video kext files. So even though I may successfully change vendor/device IDs, the kext that gets loaded to match has probably been changed by me and isn't working as it should. Your mileage may vary, hopefully for the better. I also don't have any DVD's handily around to check if DVD player works. Core Image and Quartz Extreme are not available with my current settings, so I'm guessing no.

Playing around with video card vendorID, deviceID and name as well as display-family, display-config-info and graphic-options:
sudo nvram boot-command='dev screen
" vendor-id" delete-property
" device-id" delete-property
" subsystem-vendor-id" delete-property
" subsystem-id" delete-property
" name" delete-property
" width" delete-property
" height" delete-property
h# 610 encode-int " vendor-id" property
h# 9c0a encode-int " device-id" property
h# 0 encode-int " subsystem-vendor-id" property
h# 0 encode-int " subsystem-id" property
" ATY,RageM3p29s" encode-string " name" property
h# 400 encode-int " width" property
h# 300 encode-int " height" property
dev /
" display-family" delete-property
h# 2 encode-int " display-family" property
0 encode-int 2 encode-int encode+ " display-config-info" property
0 encode-int " graphic-options" property

Have fun.


This is great! Making it into a clickable script shouldn't be hard; I know that you can run terminal/UNIX commands using AppleScript. I'll have to investigate this further.

Did Core Image or Quartz Extreme ever work? I was thinking the video adapter can't support it at all.

Incidentally, I upgraded to Tiger and discovered my brightness settings were gone. I applied the hack someone (I think it was you) had linked to on MacMod, and it worked. I'll be posting about that as soon as I can (I'm in Chicago right now).

I've played with DVD player some more. VLC works, but it's super jerky. I've tried some other players, and the only ones that seem to play smoothly must be using the same method that Apple's own software uses, because the screen is black.

Since you got it working at one point, there has to be a way of doing it - it's just finding the magic combination.

re:dvd playback

Yeah, I remember many times getting the holy grail mode with smooth dvd playback...until plugging anything into the audio jack kills it. I took many screen shots of settings, vendor/model #s, screen parameters etc.. but no combination of forcing them seem to work. I am surprised that display-family of 2 comes up as 1024x768. Wasn't that the 1152x768 mode before?!?

It's probably some other snafu of the os trying to sniff out what's really there that causes HG mode to work. I was looking through all of the words (commands) available in OF and see where one could even insert whole nodes of hardware that aren't really connected.

This new way of editing OF came about because I wanted to install Leopard on my PowerbookG4 PPC at 800mhz. The cutoff cpu speed was 867Mhz. I found a tutorial on how to change the cpu speed in OF via the boot-command field...which I though was only for basic command line switches like graphics-mode=1024x768x32 or cpus=1 etc. It was very cool to find out that all of the OF words/editing is available via boot-command. I tried playing around with putting the commands into a text file and linking it to the nvram boot-script variable, but it never worked.

Enjoy Chicago. Later.


Re: dvd playback

You guys are great. I'm borrowing the idea to fix my iBook G4. I replaced the faulty logicboard a while back. And now the LCD won't work, most likely the new board is using Chi Mei LCD panel instead of LG There's lot of info here and research to let me try fiddle around. I just want to say thanks to all of you! Hope I can get a clamshell and join the gang too.


didn't work 4 me...

but then i'm trying it on a 366 f/w...it plays DVDs fine, but then here's the ouptput of sys_prof:


      Chipset Model: ATY,RageM3
      Type: Display
      Bus: AGP
      Slot: ATI
      VRAM (Total): 8 MB
      Vendor: ATI (0x1002)
      Device ID: 0x4c46
      Revision ID: 0x0002
      ROM Revision: 113-XXXXX-119

hmmm, no display? i'm lookin' @ it (see my install pix @ wibles.webhop.net/toms/iBookMod)

so i ran sys_prof on my 466 clamshell (target of the new display, but since it's the wife's, i thought i oughta get it working b4 i tear it up;-)
and lookee here:

      Chipset Model: ATY,RageM3
      Type: Display
      Bus: AGP
      Slot: ATI
      VRAM (Total): 8 MB
      Vendor: ATI (0x1002)
      Device ID: 0x4c46
      Revision ID: 0x0002
      ROM Revision: 113-XXXXX-119

i-den-tickle;-\ now what, kimosabee? i'll try the OF hack now...

Re: didn't work 4 me...

I believe this might only work for the 466Mhz motherboard. I haven't tried it on any other models.

looks like my 2nd post didn't make it...

using the OF hack (setting nvramrc) my 366 displayed 1024x768:-) it's the same display card, so i would expect it to work...see the last 3 pix @ http://wibles.webhop.net/toms/iBookMod

OF hack worked!-)

366 f/w!!! check out the last 3 pix on my webpage:-)

i would imagine that you can edit the nvramrc entry...

yes, it does work...

sudo nvram nvramrc='dev /
3 encode-int " display-family" property'

gives 1024x768.


Terminal wont work

I do everything you say, but when I hit mac-boot' and it tells me to enter my password I can't enter anything, its like my keyboard stops working the only thing that works is enter, and it tells me 'sorry try again'. What can be wrong?

Re: Terminal wont work

Mine doesn't ask for a password. Sounds like you have the open-firmware password set. If you didn't set it, and you need to reset it, I think there's a way. Google on how to reset open-firmware passwords. Once you've cleared the password, then try this again.
Good luck.

Re: Terminal wont work

So you've definitely tried carefully typing in your password and hitting enter?

OF, like Unix and Linux, doesn't show any feedback as you type in a password. It's blank the entire time, with no cursor movement or anything.


just had to reset pmu/pram/nvram for a new battery, now all i get is 800x600 on 2/3s of the screen:-( tried boot-command method, no joy; tried nvramrc method no joy:-( wtf??? i'll try the long version of boot-command... oh, and did i mention the timezone on the menubar clock cannot be set to anything other than gmt?



the long version of boot-command worked, i'm back in bidness:-)

now if i can fix the timezone problem, & hope thge battery won't die @ 19% indicated...

Re: crap:-(

Sounds like something else is whacked? Try resetting the pram again, (be good to clear out the open firmware version) shut it down and then reboot it. Then try both versions of the terminal versions. Can't offer anything else. Drag it stopped on you! Good luck with it.

got it working again, thanx:-)

your long boot-command fix works:-) dunno which param did the trick, i'm on vacation now so i'm not up 4 debugging;-}

btw, watched a dvd last nite on external screen, and the brightenss keys worked again! unfortunately only when the external cable is plugged in:-{

Re: got it working again, thanx:-)

That's great. I remember loosing the 1024x768 by plugging in headphones. (apparently it forced a display check) Be careful if thinking of using an external monitor AND external audio.

not a problem...

plugging in the ext.cable switches the display to 800x600, unplugging switches back to 1024x768:-)

maybe a plain headphone jack is confusing the display detection? haven't tried it myself...

Re: not a problem...

It may be because of how the hardware deals with an external display. The iBook can only mirror its own display, so the output on that 3.5mm jack is likely hardcoded to do 800x600, since that's the iBook's normal resolution.

I'm not sure if there's a way around this. I also don't remember off the top of my head if I had this problem. I'll have to mess around with it once I find my iBook (we just moved).

d'oh! gone again...

just rebooted, saw a flashing icon i've never seen: looked like a globe w/n&s america...must be the new world icon? anyway, it flashed for maybe a minute, then got the os9 sys folder alternating w/the question mark folder, then osx finally booted...but only in 800x600:-( now where's those nvram scripts i wrote...


used the long form: the short version didn't work...
iBook Mod

April 2013



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