Hi folks,
I just got an old iMac G3 Slot Loading and am trying to install OS X 10.4. I just swapped the HDD and RAM for something bigger, so there's absolutely no operating system on this system right now.
The issue I'm having is I'm receiving an alert:
You must update your computer's firmware before installing Mac OS X.
I found the files on the Apple site, however, I have no idea how I can install the files if I have no operating system to boot from. Any help will be great. 
To update the firmware you must first install and boot into OS 9 (Minimum of 9.0.4 - at least on my slot loader, Summer 2000) and then run the Firmware Update Utility (or somthing along those lines, I did mine a fair while ago now). Then you will have to boot into OpenFirmware yada yada yada to apply the firmware update (applies itself once in OF - or at least mine did) Once you have updated your firmware you can then Install 10.4 as normal. Once 10.4 is installed perform ALL the updates so you are running a patched system, then if you are running it on the internet download TenFourFox to use as your web browser. Once all this is done your sweet. Oh by the way which Slot loader model (Color, CPU Speed etc)?
I think it's the Summer 2000 one. Came with a 6GB drive, 350MHz processor and 64MB of RAM. Sorta like a lighter Bondi-Blue color.
I guess I'll have to disassemble it again to pop the OS9 drive in. Is there any way I could boot it up without having to rip it apart to access the drive, like popping it into an external case?
If you have a Firewire 400 external case you should be able to stick a bootable OS9 drive into that to boot from, I have also occasionally had some success with a USB Hard Drive but it was PAINFULLY slow over USB 1.1. I have found though that without an authentic Apple Keyboard you MAY have some issues booting from a device other then the internal Hard Drive or CD/DVD. Other than that have fun
Understandable. When I bought it, the system came with all the original parts (keyboard/mouse). Was quite surprised.
I'll try to do a USB boot to see what happens.
Also, while I'm on the topic of this system, it seems that I've got a tiny problem with the CRT. It's gone all blue. (See attached image in link). I think it may be dust on the CRT, considering it was extremely dusty when I bought it.
It was working last night fine but when I booted it this morning it was gone all blue.
http://i.imgur.com/6WeS3.jpg
I don't get it, your photo shows a system. Were you able to transfer the OS9 over with USB? That blue screen does not look promising. Those models are famous for developing faulty PAV boards.
There are two other ways you can get OS9 onto that machine--starting the iMac up in firewire target disk mode to mount it's hard drive on another Mac, or by simply creating an OS9 CD by burning your OS9 onto a CD, boot up the iMac from the CD, and then drag and drop the OS9 that's on the CD onto the iMac's hard drive. You could even burn the firmware update onto the CD as well and just run it from the booted CD and not have to put OS9 on the hard drive at all. I don't remember, but I think you might have problems installing Tiger on a CRT iMac. They were able to install Panther, but like the B&W, Tiger does not simply install.
Getting a bootable system was sorted out earlier in the thread, as for running tiger on a CRT iMac as long as it is a slot loader it can run 10.4.11 without any help what so ever.
As for the whacked out display before writing it off as a bad PAV/Tube/etc try calibrating the tube, I know you can in OSX but not so sure about OS9. Only then explore other options about bad hardware.
I booted up in OS9 and got the firmware update completed. As soon as the firmware update was started, it went back to normal. I think it was just dusty, there was about a 1/16 inch of dust on over the system so a can of compressed air and a good blow out I think wouldn't hurt it.
swinsor, I didn't say there was any problem running Tiger on a CRT iMac. I said there might be a problem installing Tiger on a CRT iMac, as in, using the Tiger install disk to install. My memory may be faulty about that, but I seem to remember there was a problem with that with both the iMac and the B&W. Both machines were past their support life by the time Tiger came out, or something to that effect. I've simply been using Carbon Copy Cloner to copy systems onto iMacs for a long time, and yeah, Tiger runs fine as long as you have enough memory.
I can garantee that on a 400mhz or higher (perhaps even the 350mhz) Tiger is an oficially supported operating system and will install fine on a CRT iMac, as for the B/Ws I think your right about Tiger not being officially supported.
Wow, fast response. I guess my memory is just about the tray loaders. I'm certain you can't use the Tiger install disc with those.
I got an old B&W that has 10.4 on it, works perfectly. My old tray loader is still stuck on Panther, but 233MHz just isn't that powerful.
Since the internal CD drive is a bit rough inside that system, I'll hook my external DVD drive up and boot from that to install the OS from DVD. Hoping that there will be no problems during the install.