Can't upgrade from OSX 10.6.8 on Mac Mini 2,1

That's a Mac mini (Mid 2007).

According to MacTracker,

• The most recent Mac OS you can run on it is Mac OS X 10.7.5 (Lion). You can't install Mountain Lion or newer.
• There are two RAM slots. The official maximum is 2 GB of RAM; the actual maximum is 3 GB.

You can use a Web browser to get a .DMG containing the Lion installer from here:

How to download and install macOS - Apple Support

I'm not sure if this will get you a different .DMG than the one available through the link that you posted, or simply another copy of the same thing.

The only apparent objection would be an unsupported memory configuration. That Mac supports a maximum of 2 GB RAM. 3 GB and "you're on your own". 4 GB is uncharted territory.

OS X installers perform certain fundamental checks before they will even begin to assure the likelihood of success. I suspect that is the limitation you are encountering. Remove the offending RAM and try again.

How can I install OSX 10.7, or something newer?

I strongly suggest you consider HWTech's recommendation to install Linux on that Mac. It is much newer and will run much better than any version of OS X ever did — even with an old spinning HDD.

I happen to know Lion for example would absolutely choke with its minimum specified 2 GB RAM anyway, whereas that will be a comfortable amount for Linux. You will be amazed at how well it runs on such modest hardware.

I believe you may have been misled into assuming a lack of hardware drivers. I don't happen to have that model Mini but I have a similarly aged iMac and everything works perfectly. That does not mean you might not have to do some legwork to find appropriate drivers but don't let that stop you. There are plenty of resources to draw upon.

In any event the first and most fundamental step is to revert the hardware to a supported configuration. Fix hardware before software. Upgrade memory when you confirm everything works and you are in position to experiment.

Best of all possible worlds: Leave the Snow Leopard installation intact and install Linux on a separate partition. In such a dual boot configuration the Mac will be better than it was when it was new.

Cal_ab wrote:

I know that Linux won't work fully either, due to drivers not being available (e.g. sound)

Are you sure? I never used Linux on that particular model that I can recall, but have installed & used Linux on the 2007-2009 white MacBooks booting from an external USB drive (most likely used it with MBPros as well). The only "issue" for those laptops was making sure to take the iSight Camera firmware file from OSX 10.6 Snow Leopard (or its installer) so the built-in camera works. I wouldn't expect sound to be an issue on a Mini (I've never encountered a sound issue with any older systems).

Did you try the Linux Mint "Live" mode on the Linux Mint USB installer? It is possible the "Live" mode option may have some issues, but the full installation should be Ok (or can be made Ok).

You can also try creating a bootable Knoppix USB stick to test the Mac Mini 2,1 (2007 model) hardware compatibility. Knoppix was made to work with a lot of different model computers, so if Knoppix is able to work with the audio or other hardware components, then Linux Mint can be made to work as well. Just don't install Knoppix because it is not really made for everyday use. Try Knoppix CD version 7.2.0 (not the ADRIANE version...scroll down further for the standard one) since I know it worked on the older Macs. The v8.6.1 & v9.x DVD ones should also work, but I haven't tried them on such old systems. You want the ISO image with "EN" in the name for ENglish. Later versions of Knoppix may handle some hardware better than older versions, but I have encountered more video related boot issues with the later versions of Knoppix.

Use the downloaded ISO file as a source for Etcher (Mac, Windows, Linux) to create the bootable Knoppix/Linux Mint USB stick. You will need to Option boot the Linux USB stick & select the orange icon labeled "EFI". You must give Knoppix lots of time to finish booting since the Mac may appear frozen on the Apple boot picker menu (it is an Apple firmware & Knoppix compatibility issue regarding video output during the early boot process).

Once Linux is installed & configured, then Linux will just keep running without any issues. Unfortunately some hardware may initially require a bit more manual setup & configuration of Linux, but once you have the hardware working...you are good to go. More recent versions of Knoppix & Linux in general tend to have fewer hardware compatibility issues.

I'm not pushing you here, just thought I would offer some tips from years of experimentation. I just like to keep older devices running & being useful for as long as the hardware is actually willing to work. Feel free to completely disregard this post, there will be no hurt feelings.

VikingOSX wrote:

When you upgrade to Lion (10.7.5), you will lose the ability to run any AppleWorks suite as the Rosetta 1 byte-code translator (PPC to Intel) was dropped. So was the ability to apply PDF hyperlink annotations in Apple's Preview.

Owing to the ancient security code in Lion, you will likely lose most connectivity with modern, secure websites, and email servers too. Browser vendors now only support Catalina and later.

Neither Snow Leopard nor Lion are likely to have much success browsing modern https Web sites. The changes to handle modern https security first went into El Capitan, although they may have been back ported to Yosemite. The browsers that run on El Capitan may work a little better than the ones that run on Snow Leopard, but they are way out of date, too. (Firefox 78 ESR has not gotten security updates for several years, and I'm not sure that it is even still available for download.)

And as you point out, Lion made a snack out of dear Rosetta.

At this point, it may be better to stick with Snow Leopard than to go to Lion.

When you upgrade to Lion (10.7.5), you will lose the ability to run any AppleWorks suite as the Rosetta 1 byte-code translator (PPC to Intel) was dropped. So was the ability to apply PDF hyperlink annotations in Apple's Preview.

Owing to the ancient security code in Lion, you will likely lose most connectivity with modern, secure websites, and email servers too. Browser vendors now only support Catalina and later.

Servant of Cats wrote:

(Firefox 78 ESR has not gotten security updates for several years, and I'm not sure that it is even still available for download.)

It is. Mozilla maintains a massive archive of all previous versions including that one.

https://ftp.mozilla.org/pub/firefox/releases/

I needed an ancient browser to administer an equally ancient device running an even more ancient OS. Without that old FF version that device might have been consigned to the scrap heap.

You're probably better off with it running Snow Leopard, since certain legacy software will not work with anything later. In other words, for an obsolete Mac, Snow Leopard is preferable to Lion.