Late 2009 27" iMac - no OS

[DCBassman]

Picked this up for a song yesterday. It's my second Mac, after a short relationship with a 2,1 Mac Pro.
It's running, perfectly well, Linux Mint 21.1.
I'd like to at least try it with High Sierra, but how to obtain the software? I have no access to another Mac. Once I have the install package, a bootable USB seems straightforward.
Can anyone point me to a solution, please?

 

[theMarble]

Can you get into Recovery Mode? You can hold either CMD+R (local recovery) or CMD+Option+R (internet recovery).

Otherwise, do you know anyone that you could borrow a Mac from? Without a Mac, creating a USB stick is unlikely to work at best.

 

[TheShortTimer]

Can you get into Recovery Mode? You can hold either CMD+R (local recovery) or CMD+Option+R (internet recovery).

Otherwise, do you know anyone that you could borrow a Mac from? Without a Mac, creating a USB stick is unlikely to work at best.

Good advice - whatever version of macOS is provided, they could then use it to leapfrog to High Sierra. As an alternative if that doesn't work out and they're unable to obtain access to another Mac, I found this thread on the Linux Mint forum that might be helpful to the OP on how to create a MacOS USB installer from within the Linux environment.

Here's a link to the Sierra installer: they could download that on Linux Mint to create a USB stick and once it's installed, then use it to upgrade to High Sierra. It's likely that the time and date will need to be adjusted from the Terminal to get around the expired certificate issue.

Before you install, set the clock on the Mac to a date when the certificate was valid, perform the install, and then reset the date back after installation. To change the date from Terminal (which is likely all that will be accessible), follow these steps, which set it to 1 February 2016:

1. In the installer, choose Utilities > Terminal.
2. Enter sudo date 0201010116, press Return, and enter your password.
3. Quit Terminal and continue the install.

Personally I'd go straight to Catalina with the DosDude patcher as its compatible with their model.

 

[DCBassman]

Definitely no recovery mode. The only key that work is Option, to choose something bootable. I'm in the process of trying to use Transmac to create something that gets me some sort of MacOS running, but no joy yet.

 

[DCBassman]

Basically, I have a Mac with a blank disc. Despite lots of USB creation options online, none of them show up as bootable. The hardware that detects that is working: if I stick a live Linux stick in, there it is, no problem, using Option>power.

 

[Amethyst1]

Basically, I have a Mac with a blank disc. Despite lots of USB creation options online, none of them show up as bootable.

Did you try an installer that has already been converted to a bootable ISO, such as this (disclaimer: I have no idea if it works)? Write the ISO to a USB drive using e.g. balenaEtcher or dd.

Can you get into Recovery Mode? You can hold either CMD+R (local recovery) or CMD+Option+R (internet recovery).

Local recovery requires the hidden recovery partition to be present on the HDD, and the Mac may be too old to have gotten the firmware update to add support for Internet Recovery (I think it was only for 2010 and later models).

 

[DCBassman]

Did you try an installer that has already been converted to a bootable ISO, such as this (disclaimer: I have no idea if it works)? Write the ISO to a USB drive using e.g. balenaEtcher or dd.

Trying that now...

 

[DeltaMac]

20009 iMac is too old for internet recovery, and if the Linux system was installed to a clean/reformatted hard drive, then no recovery system. The only choice will be an external bootable installer. Hopefully, the hints above about making a macOS bootable installer from Linux will help you out.

 

[chaosbunny]

If all else fails you could try to get a cheap Snow Leopard (Mac OS 10.6.) DVD, install it and update from there. This was the last Mac OS to be shipped on a DVD and it's also the OS your iMac came with in 2009. Just looked and found one on ebay for $ 16.

 

[Amethyst1]

If all else fails you could try to get a cheap Snow Leopard (Mac OS 10.6.) DVD, install it and update from there.

The original 27" iMac shipped with 10.6.1, so the retail disc should be 10.6.3 to ensure it'll boot and install.

 

[DCBassman]

Did you try an installer that has already been converted to a bootable ISO, such as this (disclaimer: I have no idea if it works)? Write the ISO to a USB drive using e.g. balenaEtcher or dd.

Trying that now...

Right, that link plus Etcher got me booted to...something. I presume I must now prepare the drive in some fashion.
OK, ploughed my way yjrough Disk Utility, went back to "Install..., selected that disk, and it appears to be installig.
Exciting!

 

[DCBassman]

My Apple peripherals are even more ancient than the machine. An A1048 keyboard and a wireless Mighty Mouse. But they still do what they are supposed to do, so no complaints there. Just waiting now for the installer to do its thing.

 

[DCBassman]

Well, all good to a point, but it won't let me agree to the terms and conditions after signing in. Irritating...

 

[DCBassman]

OK, 'tis done! And very nice too. Next: more RAM, clone the disk onto an SSD. Then sort out the tools needed to actually install it!
Thanks for all your input, everyone!

 

[DCBassman]

Personally I'd go straight to Catalina with the DosDude patcher as its compatible with their model.

I did try this, but it failed. Possibly because the machine is in a non-standard state? Anyhow, it's running HS well.

 

[TheShortTimer]

I did try this, but it failed. Possibly because the machine is in a non-standard state? Anyhow, it's running HS well.

Great news that macOS is available to you and it's running well. I also had problems initially with getting the Catalina patcher to work. If you want to make another attempt we can try and ascertain what the stumbling block is.

 

[MultiFinder17]

20009 iMac is too old

Duh, the 20009 iMac is too old for pretty much anything other than word processing and light web browsing. I hear its CPU can only calculate the precise interactions of subatomic particles on the galactic scale, not even between galaxies! You need a 20021 iMac, bare minimum, to get any work done. Don’t forget to upgrade the RAM to at least 128 zettabytes to make sure animations don’t lag.

 

[B S Magnet]

Duh, the 20009 iMac is too old for pretty much anything other than word processing and light web browsing. I hear its CPU can only calculate the precise interactions of subatomic particles on the galactic scale, not even between galaxies! You need a 20021 iMac, bare minimum, to get any work done. Don’t forget to upgrade the RAM to at least 128 zettabytes to make sure animations don’t lag.

“The year is 20023 C.E. There is only one company in the galaxy. That company’s name is Apple…”

Please contact your member of parliament or representative to support passing anti-trust legislation today.

V.O.: This public service announcement supported by the old coots and maids on the MacRumors Early Intel Macs forum.

 

[MultiFinder17]

“The year is 20023 C.E. There is only one company in the galaxy. That company’s name is Apple…”

Please contact your member of parliament or representative to support passing anti-trust legislation today.

V.O.: This public service announcement supported by the old coots and maids on the MacRumors Early Intel Macs forum.

On the downside, we live in a kleptocracy ruled by Steve LXXIII that controls everything we can and cannot do.

On the plus side, after 18000 years people finally agree that yes, Safari finally feels snappier.

 

[B S Magnet]

On the plus side, after 18000 years people finally agree that yes, Safari finally feels snappier.

“…the beatings continued until browsing morale finally improved…”

 

[DCBassman]

Excellent use of that typo, much applause!

 

[Ausdauersportler]

I did try this, but it failed. Possibly because the machine is in a non-standard state? Anyhow, it's running HS well

You can replace the video card with an AMD 2012+ model with metal support. This way you could use OCLP instead of the ancient patcher and run all macOS versions including Monterey without any problems, even Ventura runs pretty well. A reasonable priced M5100 will do the job. Monterey is the best working target.
Check links in my signature…

 

[DCBassman]

You can replace the video card with an AMD 2012+ model with metal support. This way you could use OCLP instead of the ancient patcher and run all macOS versions including Monterey without any problems, even Ventura runs pretty well. A reasonable priced M5100 will do the job. Monterey is the best working target.
Check links in my signature…

I could, and I will be going inside it at some point for drive upgrading, but to be honest, it's the machine I like, not macOS, so will likely run Linux Mint and use it as a daily driver. Even these graphics will be more than enough for my normal use. No heavy lifting on my computers, or not yet, anyhow! That might change if I start to do music recording, but I have an i7-powered machine for that at the moment. However, because I like the hardware, I might just try and pick up the i5-powered 21.5" version of the 2009 iMac, they seem to be cheap and plentiful.

 

[retta283]

However, because I like the hardware, I might just try and pick up the i5-powered 21.5" version of the 2009 iMac, they seem to be cheap and plentiful.

This may just be a typo, but there is no 2009 21.5" iMac with an i5. Only a Core 2 Duo. 2010 was first year with i-series chips for the 21.5", but i5 was only available through BTO.

 

[Amethyst1]

[…] I might just try and pick up the i5-powered 21.5" version of the 2009 iMac, they seem to be cheap and plentiful.

As pointed out, the 2010 was the first 21.5” with an i3/i5 but these were only dual-cores. If you want a quad-core, you need a 2011 2012 or later model. (I’d not touch a 2011 because of widespread GPU failures).