MP 1,1-5,1 New MAC Pro 4.1, no HDD, where to start?

[reader50]

BTW, what is the highest OS the 3,1 can go?

Highest Apple-supported macOS versions:
Mac Pro 2008 (3,1) - El Capitan (OS X 10.11.6)
Mac Pro 2009 (4,1) - El Capitan (OS X 10.11.6)
Mac Pro 2010-2012 (5,1) - Mojave (OS X 10.14.6) with Metal-compatible GPU (or 10.13 without metal GPU)

The 4,1 can be flashed with 5,1 firmware to make it a 5,1 for all practical purposes.

Unofficially, you can use the dosDude patchers to upgrade a 3,1 or 4,1 to Sierra (10.12), High Sierra (10.13), Mojave (10.14), or Catalina (10.15). It will take a 5,1 to Catalina. Note that you really should use a Metal-compatible GPU for Mojave or Catalina.

If you go to Mojave or higher with a 5,1 be sure to stop at Mojave at least temporarily, to update to the latest 5,1 firmware. Later macOS versions (and some peripherals, like M.2 devices) will work a whole lot better (or at all) with the latest 5,1 firmware. See this thread for details.

Unoffically, you can use OpenCore Legacy Patcher (OCLP) to update a 3,1 or 4,1 or 5,1 to Big Sur (11) or Monterey (12). OCLP is able to make a non-Metal GPU work, but you need a metal GPU to do the firmware update in Mojave. So you need at least one Metal GPU for 4,1 or 5,1 updates.

Metal-compatible GPUs: AMD (Radeon HD 7xxx or higher), nVidia (GTX 6xx/7xx or 9xx/10xx with web drivers). This is only a general guideline - check the GPU stickies for more specific info. Also, it's best to avoid nVidia cards, especially for recent macOS versions. Apple dropped support for them long enough ago, that the cards have aged and drivers are badly outdated.

OCLP will go higher, to Sequoia currently, and Tahoe is in the works. However, there are GPU restrictions (no AMD navi cards) for a 2008-2012 Mac Pro. The lack of AVX opcodes in our CPUs also causes some software to fail - you need software versions compiled without AVX codes. If the software says it will work in Monterey or earlier, it will work in our OCLP installs of Ventura through Sequoia. Presumably Tahoe as well in the future.

 

[Oldmopars]

I have been attempting for the last 2 days to get El Capitan. The Apple web site does not work. When I click on it, the page flickers, but it does not download anything. So, I tried the App Store. That does not work because my Macbook Pro is a 2023 and it is too new. It won't let me download it.
I have tried going to the Internet Archive, It at least tried, but failed to download.
I have tried to get it from the Mac Pro, but it is running Lion and even though the internet is connected, Safari will not connect to any pages. I assume security?
What do you suggest I do to get El Capitan so I can put it on my 4,1?
BTW, same issue with the 3,1 .

 

[Oldmopars]

Highest Apple-supported macOS versions:
Mac Pro 2008 (3,1) - El Capitan (OS X 10.11.6)
Mac Pro 2009 (4,1) - El Capitan (OS X 10.11.6)
Mac Pro 2010-2012 (5,1) - Mojave (OS X 10.14.6) with Metal-compatible GPU (or 10.13 without metal GPU)

The 4,1 can be flashed with 5,1 firmware to make it a 5,1 for all practical purposes.

Unofficially, you can use the dosDude patchers to upgrade a 3,1 or 4,1 to Sierra (10.12), High Sierra (10.13), Mojave (10.14), or Catalina (10.15). It will take a 5,1 to Catalina. Note that you really should use a Metal-compatible GPU for Mojave or Catalina.

If you go to Mojave or higher with a 5,1 be sure to stop at Mojave at least temporarily, to update to the latest 5,1 firmware. Later macOS versions (and some peripherals, like M.2 devices) will work a whole lot better (or at all) with the latest 5,1 firmware. See this thread for details.

Unoffically, you can use OpenCore Legacy Patcher (OCLP) to update a 3,1 or 4,1 or 5,1 to Big Sur (11) or Monterey (12). OCLP is able to make a non-Metal GPU work, but you need a metal GPU to do the firmware update in Mojave. So you need at least one Metal GPU for 4,1 or 5,1 updates.

Metal-compatible GPUs: AMD (Radeon HD 7xxx or higher), nVidia (GTX 6xx/7xx or 9xx/10xx with web drivers). This is only a general guideline - check the GPU stickies for more specific info. Also, it's best to avoid nVidia cards, especially for recent macOS versions. Apple dropped support for them long enough ago, that the cards have aged and drivers are badly outdated.

OCLP will go higher, to Sequoia currently, and Tahoe is in the works. However, there are GPU restrictions (no AMD navi cards) for a 2008-2012 Mac Pro. The lack of AVX opcodes in our CPUs also causes some software to fail - you need software versions compiled without AVX codes. If the software says it will work in Monterey or earlier, it will work in our OCLP installs of Ventura through Sequoia. Presumably Tahoe as well in the future.

My current issue is that I just can't get El Capitan. The Apple site does not work, 10.10-10.12 only cause the page to flicker, no download. My Macbook Pro is too new for El Capitan and because the 3,1 and 4,1 are both on Lion, the internet is connected, but will not open any of the sites.
My daughter has a 2017 iMac and my wife has a 2015? Macbook Air. I may try it on those and see if I can get anything.

 

[reader50]

If you're doing it from within Lion, the security certs within your old Safari copy are long expired and most of the web is https today. Use the direct download options, but on something more modern. On your MBP, if Safari isn't doing it, try some alternate browsers - the links should work. Firefox, Opera, Brave, etc.

You can also try the App Store from within Lion. That should offer the installer app for El Capitan - if Apple's servers will accept the old security certs for an OS update. I haven't tested the Lion app store in years.