r/MacOS • u/tallgeeseR • 20h ago
Help Official MacOS full installer for 15.5, 15.6.1
softwareupdate --fetch-full-installer --full-installer-version 15.6.1
Scanning for 15.6.1 installer
Install failed with error: Update not found
Per title, any other official source where I can get them?
Trying to troubleshoot Bluetooth speaker issues that emerged on my M4 MBA after update. Problem persists after wipe off and clean install. Going to try older version per suggestion by Apple staff.
Thanks.
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u/animorphreligion 20h ago edited 18h ago
You can only get back on 15.6.1 with DFU. idevicerestore in Linux can download it for you, or use ipsw.me (but don't follow their Windows instructions with Apple Devices app, it doesn't work with Macs and breaks their firmware if you try)
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u/dlamblin 20h ago
If you had the install DMG and followed the making a bootable installer directions and reformatted the target in the process, I don't see how you could fail in going back. Every Mac OS installer release I'm aware of has a bootable media mode.
Now, I do think one of the High Sierra ones included the minimal OS dmg inside the installer app with a checksum failure if you actually try to write or mount it. So maybe that's the same for15.6.1?
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u/animorphreligion 20h ago
Maybe it could work, but Apple pulled the installers and you'd have to find one elsewhere. Mrmacintosh won't help as they post links to Apple's CDN.
I personally wouldn't downgrade to 15.6.1 after an update anyway because all 15.7+ versions ship with a newer firmware which can never be downgraded without DFU, only upgraded. 15.6.1 had the last firmware made for Sequoia era specifically, that's why if you erase the Mac on 15.7+ the reinstall option in recovery will show Tahoe and not Sequoia.
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u/dlamblin 19h ago
That's solid advice, I forgot about the various firmware upgrades that go with certain versions and their drivers. It probably wouldn't be a good idea, though it's unknown to me how much is functionally different be designed to move the support base line forward.
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u/pm_dm 19h ago
Ugh, missed that when I had to update my installation to 15.7.x to get Apple's RAW photo engine working with Canon's images again. Not sure if I'd want to risk the DFU route if I ever need to recover (I'm certainly not planning on ever "updating" to Tahoe).
Thanks for calling this out.
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u/wndrgrl555 11h ago
I have a copy but you want an official source. Apple no longer makes it available for download.
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u/mikeinnsw 10h ago
Not all versions are stored...
softwareupdate --list-full-installers
https://osxdaily.com/2020/04/13/how-download-full-macos-installer-terminal/
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u/WindozeWoes 19h ago
An "official source" is not the same thing as an "official installer."
You can get an official installer (originally taken from an official source) from a third-party; 15.6.1 is still available to download via Mist as a Firmware file, which is the ISPW you can use to restore an Apple Silicon Mac.