Previous 1 2 Next 17 Replies Latest reply: Jan 11, 2011 5:43 PM by Ralph Landry1
CerberusP Level 1 (0 points)
Hi There

I'd like know if I could upgrade the operating system on my iMac ppc from 10.4.11 to 10.5. I read a few of the forum posts and it seem that it's possible with a few tweaks. One suggestion I found is a post from tbdmoss posted on the 2nd of November, which is as follows:

It's pretty easy to get Leopard installed on any G4 machine with AGP graphics, which includes your eMac. You can make a small modification to the Leopard DVD to remove the (artificial) check for 867+ MHz if you want a DVD that will always install with no hassle, but if you just want to do one installation it's probably easier to:

(1) Hold the Command, Option, O and F keys together when starting the machine and only
release them once the Open Firmware command line has appeared.

(2) Insert the Leopard DVD into the Mac’s DVD drive.

(3) Run the following script exactly as below (including capitals), press Enter after each line
and check that Open Firmware displays “ok”

dev /cpus/PowerPC,G4@0
d# 867000000 encode-int " clock-frequency" property
boot cd:,

Will this work for the iMac I own?

Any suggestion would be greatly appreciated.



PowerMac6,1, Mac OS X (10.4.11), 1.25 GHz Power PC G4 DDR SDRAM
  • Level 8 (41,760 points)
    Welcome to the Apple Discussions.

    Your profile says you are using a 1.25 GHz iMac...and Leopard wants to see a machine with at least 867 MHz...since you meet that requirement, why do you want to run a script that fools the new operating system into installing?

    You should be able to install Leopard on your machine as it is. However, how much memory do you have and how much HD space available? Heavy duty users of Mac OS X recommend a minimum of 2 GB memory and 10 GB free HD space for the 10.5 installation.
  • CerberusP Level 1 (0 points)
    Hey Ralph,

    Thanks for replying to my post.

    To be honest I'm not sure about using the script to fool my iMac into loading the 10.5 os software. I got the idea from the forum from another person who suggested that it may be one way of initialising the 10.5 software.

    Reading you post though, I'm not sure if my iMac is able to function with the 10.5 upgrade? The memory on my iMac is 1GB DDR SDRAM. I guess that if I upgrade to 10.5 it may render the system unable to load any other software, or limit it's performance? However I have more than enough HD space. I have about 38GBs left. It has been suggested to me that the iMac I'm using can run the XOS Software to 10.5.8?

    I've only started to find out about the limitations of my system, having connected to the internet. The iMac I bought second hand, and I'm finding software I'd like to be able to use, but is limited by the 10.4.11 operating system.

    I guess it's a shot in the dark - but- any suggestions? A simple forget it would suffice. I wonder? Can I get more ram for this model of iMac? (Serial No. W83366YLPJH).

    Thanks once again for your post.

  • Level 8 (41,760 points)
    Good morning, and Happy New Year.

    To check for your iMac and the memory it can accept:

    It looks like the G4's can only take 1 GB of memory. The specs for 10.5 say it will run on 512 MB of ram, though as I said, some of the heavy duty people on here push for 2 GB. It will run on the 1 GB you have, but will run slower since it will be swapping back and forth to the HD what it would normally keep in memory. That is the way the OS runs on less memory than it really prefers. Will still work but not as fast.

    Going to faster memory won't help, iMacs are particularly picky about their memory...has to be right on spec or they get very upset and don't even boot.

    Bottom line is if you really want to use this machine for software that needs to see 10.5, go ahead, it will work. And you have plenty of free HD space so that is not a problem.

    Get back with what you end up doing and experience with it, we are all fellow users on here helping each other and like to hear how things work out.
  • Allan Jones Level 7 (33,942 points)
    Hi Ralph,

    It looks like the G4's can only take 1 GB of memory.

    That 's the original Apple spec, never updated to reflect the more recent availability of larger compatible RAM modules. When the "model identifier" (in System Profiler) got to "PowerMac6,1" the G4 iMacs could handle a total of 2G RAM. If Profiler reports existing RAM type to be PC2100 or PC2700, the the old 1G cap is not application.

    The problem is that some people do not wish to do the amount of take-apart required to get to the "factory" RAM slot. Still, if the factory slot has a 256MB module, you can, on the later iMac G4s, install one 1G module (either PC2100 or PC 2700 depending on model) in the "user" slot on the case bottom and have a total of 1.25G, usually enough for the basic stuff under Leopard.

    Several Apple models have this "extra RAM" capability: the eMac G4 with USB 2.0 logic boards, the PowerBook G4 starting with the 1Ghz 17", and others. The free and VERY handy MacTracker database calls out when the original (and always outdated) Apple RAM specs can be exceeded. It's here:

    Most RAM sites other than Crucial also provide this info. Example:
  • Level 8 (41,760 points)
    Hi Allan,

    Thanks, I am in the habit of using the kb article, almost have that one memorized now.

    Happy New Year...looks like ID has been getting a good snowfall the past few days.

  • CerberusP Level 1 (0 points)
    Hey Ralph,

    Thanks! Your a wealth of information. I'm on it, and I'll let you know how I go. I'm waiting for my 10.5 software to arrive from the States.

    In the meantime I'll check out the datamemorysystem site and see how this computer stacks up.

    thanks again.
  • CerberusP Level 1 (0 points)

    I had a look at the ram as mentioned in the Systems Profiler. It seems there are two different kind of 512MB ram... J22 and J20 (I'm not sure if this is a significant difference). It just might mean that they're plugged into different slots (guess)? They are as follows.


    Size: 512 MB
    Type: DDR SDRAM
    Speed: PC2700U-25330
    Status: OK



    Size: 512 MB
    Type: DDR SDRAM
    Speed: PC2700U-25330
    Status: OK

    I'm guessing that I can replace both of 512MB ram I currently have in the computer, with two 1GB ram?

    Is that about "ballpark" in my reckoning ?

  • Level 8 (41,760 points)
    Those are just the memory slot location identifiers, not really different ram.

    What you need to do is check with suppliers like Crucial, Other World Computing (OWC), Newegg to name three that are highly thought of by a number of the people on here. They have really good support, good customer service, return policies, and are extremely Mac-friendly.

    The memory modules you have are PC2700 Unbuffered, and the next series of numbers tell you the latency of the DIMM chips. You don't need to worry about that too much except to make sure what you buy for replacements match EACH OTHER, no shouting just trying to be clear. The Macs tend to be really picky about their memory and wanting them to be very close to each other.

    The suppliers noted above know that and are very careful about shipping the appropriate modules.

    They also have instructions and instructional videos on the web for download.
  • CerberusP Level 1 (0 points)
    Okay Ralph,

    This is what I found with the information I got from you posts.

    For the user installable memory slot I'll buy the - 1.0GB SO-DIMM Memory Module PC2700 DDR 333Mhz, and for the factory installed memory slot, I'll get the - 1.0GB SDRAM Memory Module PC2700 DDR 333Mhz.

    Now - to give my iMac real "oomph" (great word, it looks like an acronym) I thought about getting the 160GB Seagate Barracuda 2MB Buf. Ultra ATA/100 7200rpm 9.4ms Int. Hard Drive. What do you reckon? Is this lunacy?

    With great care and due diligence I should be able to upgrade the iMac.

    Any thoughts on this venture would be welcome at this stage. I'm in that head-space where I'd like to know if I have the technical bravado to actually do it. In short - fools rush in... but am I on the right track?
  • Level 8 (41,760 points)
    The memory sounds right, should make a big difference in performance of the machine. And a 320 GB HD at that faster disk speed should help performance and is a reasonable size and cost. This should not set you back too much in the money area and give a machine that is comfortable to use.

    Before ordering the hard drive, if you are going with someone like OWC or Newegg, check about the bus in your machine to see that it can support the Ultra ATA. Some of the older buses would only support ATA. The good Mac-suppliers are very good about helping with advice like that.


    PS Hope you are not in the part of Aus with all the flowing water. A lot on the news here about the area flooding over there larger than the state of Texas.
  • CerberusP Level 1 (0 points)
    Hey Ralph,

    Yeah, it's a little disconcerting with the floods in Queensland. With twenty years of drought behind them, some communities have had two consecutive years of flooding. The geography of Northern Australia is rather flat, so the floods tend to meander through the landscape inundating quite large areas of the countryside and the towns along the flood-planes. In many areas that have not received any rain at all, overnight, can become awash with floodwater from many hundreds of kilometers from where the initial downpour was.

    Fortunately where I live, about seventy kilometers south of Sydney near a city called Wollongong, it's about fifteen hundred kilometers from where all the action is. I'm as dry as a bone. Were getting just enough rain to keep the veggie garden green and productive. Thanks for the kind thoughts though. The people of Queensland are a remarkably resilient lot. We call them "Banana Benders" here in New South Wales

    The NEWS here has been reporting on the amount cold weather your part of the world has been experiencing over the last few weeks. It sounds frost-bitten. Myself, I haven't even seen snow. I think I'd hibernate in such circumstances. I hope your keeping cosy.

    Sorry for waffling on,

    I thought I'd ask you about the BUS issue. Anyway, I went to the Data Memory Systems (DMS) website that Allan mentioned in his post on this discussion, and he kindly posted the link. I got the information I needed to buy the RAM, and I watched a few youtube videos on how to change RAM and HDs.

    The DMS website page, where I found the RAM, had a link stating it led to a list of compatible hard drives for the iMac. Having said that, the hyperlink is all I'm basing an assumption I have that the Ultra ATA hard drive would be compatible.

    I'll keep on searching the net for the BUS computability issue you mentioned. Thanks, these things could be real stumbling blocks if I was not aware of them.


  • Level 8 (41,760 points)
    Hi Dave,

    That is really the great thing about these discussions, we are all fellow users, not Apple employees. So we are not obligated to push any particular supplier or branded equipment. Just have to make sure we do not offend the Apple hosts and abide by the Terms of Use.

    That bus question was something that came to mind, knowing that it is possible to buy something that won't work due to issues with older hardware specs.

    Where I live we have not had hardly any snow at all...only an inch or so before Christmas. We are described as being in the snoe hole...all around us they got clobbered. We are just cold, 24 deg F this morning.

    But last year we had a 100 year record...57 inches of the white stuff...closed things down for days.

    Post back with what you end up doing in the HD department, curious to know how things work out.

    And stick around the discussions, you are gaining great experience that you can pass along to other users. This is how we all got here, asking questions then offering help to others.

  • Allan Jones Level 7 (33,942 points)
    Happy New Year...looks like ID has been getting a good snowfall the past few days.

    And to you, too, Ralph! Oh, yes. We live in the lowest elevation spot in Idaho (~760 feet above SL at the Snake River) and still got snow before Thanksgiving, the first in the 23 years we've lived here. Right now--clear and lower 20's. Hey, the sun's out and the wind's not blowing so I think I'll take a morning walk!

    BTW, Crucial will not show any RAM that the outdated specs on the Apple sheets don't show. People trying to take advantage of newer larger modules end up having to "guess" as which Crucial RAM from another Mac works.

    That's why I like Other World Computing and Data Memory Systems--good prices and up-to-date recommendations. I have a 1G module from OWC in my wife's eMac 1.42G alongside a 256MB stick that sipped with the computer. We have 1.25G total with complete stability in a machine whose Apple spcs say 1G is the max.

    Interestingly, I saw the developers' notes for one of the G4s--can't find it at the moment--that said "max of 1G max RAM (2 x 512MB)" but added the comment, "may work with larger modules than 512MB when available."
  • CerberusP Level 1 (0 points)
    Hey Ralph,

    I thought I'd let you know how I'm going with upgrading my iMac. It certainly has been a learning curve and I've made some very fundamental goofs. It's a wonder the iMac hasn't exploded with the way I've been going about trying to upgrade it. However I think I've finally done it in, and I just tried to upgrade the operating system.

    If I step you through what I have done when upgrading the operating system, perhaps you could offer me some suggestions to alleviate the predicament I seem to be in at the moment. This post is going to be difficult for me, because I'm not a tech-head, and the situation I'm about to describe has a chronology of haphazard procedures I performed in order to try and upgrade the operating system.

    Pause for a cigarette...

    Now, where to start.

    I downloaded a 10.5 Leopard OS torrent from the internet to burn onto a DVD+R DL CD. I followed all of the procedures described in the forum to burn it onto the CD. However, when I tried to burn the software onto the DVD+R DL CD, the iMac did not recognise the CD and subsequently there I met the first of my consternation's. Having pondered the dilemma I thought of an alternative. I happen to own a MacBook, and while reading the forum for instructions on burning the CD, I happened upon a post which described using an external hard drive to perform the operating system upgrade.

    All very well... except,

    I happened to overlook a strategic step in the upgrade procedure. I remember from the forum something about 'partitioning the hard drive' on the destination volume, or something like that. <:-\

    Anyway, I connected a firewire between the iMac and the MacBook and setup a network between the two devices. I then opened the image of the Leopard operating system on the MacBook and proceeded to opened the disc utility. I clicked on the restore menu radio button in the disk utility and dragged and dropped the image of the Leopard OS, as per instructions, into the source field. I then dragged and dropped the image of the iMac HD into the destination field and pressed restore. It all went along smashingly.

    After the download to the iMac was complete, I followed subsequent steps. I was advised to restart the MacBook, where I was assured the Leopard OS would begin the upgrade procedure. It did, although the other way. Somehow I ended up with the Leopard OS on my MacBook when I was intending to upgrade the iMac. Serendipity, I only had 10.4.11 on the MacBook, and now I have Leopard! Great huh?

    My delight was short lived.

    Remember the partitioning of the destination hard drive I overlooked earlier? It seems I've given my iMac an identity crisis. I have caused what is affectionately known as 'the spinning wheel of death'. Apparently the iMac can no longer distinguish between the Leopard OS and Tiger. The i Mac proceeds no further than the grey screen with the Apple icon and the spinning wheel. I can still access the iMac and all of the data on it through a firewire network, but I'm uncertain of how to restore either of the operating systems.

    Meanwhile, the Leopard OS on the MacBook has very nice features.

    Is my iMac ruined?

    Please help!

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