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2018 mini, install big sur on external ssd or thumbdrive break 4k hdmi?

harriska2

harriska2

macrumors 68000
Original poster
Mar 16, 2011
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Oregon
I’m wondering if anyone has installed big sur on an ssd or thumbdrive for their their 2018 mac mini. I need to see if I can move to big sur without breaking everything first. I’m concerned it will upgrade the mini’s firmware that will affect my monitor, even if I end up not using big sur and stay with my current mojave. I have a 40” Samsung 4k chroma 4:4:4 that works beautifully right now on hdmi and I want to continue to be able to use it. If anyone has successfully installed big sur on an external, what form factor and connection did you use? (Thunderbolt ssd? usb 3 256 gb thumbdrive?)

Also curious if these directions would work on a 2018 mini:

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Big Sur works fine on USB or Thunderbolt. Changes to firmware will not affect your monitor (you can go back to Catalina if something changes).

Thumbdrives may be slow - make sure it can do at least 400 MB/s. Use a NVMe enclosure for 1000 MB/s (USB 10Gbps) or 3000 MB/s (Thunderbolt - only some NVMe can do 3000 MB/s).

If a problem occurs with HDMI port, unplug power from the Mac mini 2018 for 30 seconds.
 
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I always install the new version of macOS on a external practice drive first.

I did this with every single release of macOS Catalina and based on my assessment of the software quality, I never upgraded my boot drive to Crapalina.

I've done this with Big Sur as well. Heck, I've probably been doing this 7-8 years, when creating a bootable USB install thumb drive for OS X installations became possible.

With Apple's current software QA standards, it will be a cold day in hell before I blindly upgrade my boot drive to Apple's latest and greatest operating system.

Note that the operating system upgrade may upgrade the firmware whether it be jumping from Mojave to Catalina, Mojave to Big Sur, or Mojave to a later version of Mojave (including Security Updates).

As far as I know there is no downgrading the firmware (T2 Security Chip) nor does anyone here know if every single firmware work with every single monitor and monitor setting combination. All I know is that my Mac mini 2018 has continued to display to my two monitors (LG 27" UHD & Dell 32" QHD).
 
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I don't use external drives as primary boot drives so I tend to choose more affordable components since they are not deployed for everyday operation.

I have a couple of the SSK m.2 enclosures ($20 apiece from Amazon) and whatever decent PCIe Gen3 drive was on sale. I've used Sabrent Rocket, ADATA XPG, and Samsung.

The Samsung drive you linked to looks like a good product for its price (Samsung SSDs are great) but I don't need TB3 performance for my usage case. That might be a great on-the-road scratch drive for multimedia applications for a MacBook though.

I always buy the OEM drive and the enclosure separately. I think I have only purchased one pre-built named brand drive in the past twenty years. (It was an external Seagate 3.5" HDD spinner for a killer price.) Not that they don't exist, I simply rarely look for them.
 
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"I’m wondering if anyone has installed big sur on an ssd or thumbdrive for their their 2018 mac mini"

Big Sur will install just fine on a USB hard drive (either SSD or platter-based), but it WILL NOT INSTALL onto a USB flashdrive.

I tried it on several flashdrives, one was 64gb, the other 128gb.
The install started but wouldn't complete.

Perhaps someone else got this to work, but I couldn't.

If you want to experiment with BS on an external drive, I'd suggest an SSD mounted via USB3.
Or perhaps an nvme blade drive in a USB3.1 gen2 enclosure.
500gb is "all you need", but even 250gb will do fine.
 
Fishrrman said:
Big Sur will install just fine on a USB hard drive (either SSD or platter-based), but it WILL NOT INSTALL onto a USB flashdrive.

I tried it on several flashdrives, one was 64gb, the other 128gb.
The install started but wouldn't complete.
Click to expand...
Were these flashdrives GUID partition types or MBR? If you don't know, they were probably MBR which hasn't been compatible as a macOS boot drive for several generations of macOS.
 
"Were these flashdrives GUID partition types or MBR?"

It's been a while, but seems to me I took the time to erase them to APFS with GUID partition format before I did the [attempted] install.

Didn't make a difference.
The install went -almost- "all the way through".
Then, hung forever at "about a minute to go..."
 
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