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Testing Apple releases on external drive

T

tommiy

macrumors 6502
Original poster
Dec 11, 2015
420
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I've a question that I am interested in how this is addressed by others. When sitting on Mojave and wanting to test Catalina I used CCC to clone my drive, booted from the external drive, and then installed Catalina. However, when I then return and boot from my internal drive Mojave complains that the EFI firmware is now not the correct versions....obviously because of the firmware upgrade performed by the catalina install. How do I get the firmware to go backwards? Seems the only way may be to do a full fresh install of Mojave from scratch and then migrate all my files back.

So my question is, for all those that test Apple releases, how are you now doing it and maintaining the correct firmware for the release?

Appreciate any responses.
 
I've tested Apple beta systems on an external drive many times. And I used the same method as you; CCC clone and then boot from the clone. I did the same with Catalina and was running Mojave at the time. However, I never encountered a firmware error.

I really don't understand how you would get a firmware error when booting again from Mojave. Did you eject the external drive after booting back to Mojave?
 
I actually did some hunting through the logs and discovered that there is a eficheck tool that runs on a cron job once a week to validate the firmware versions against apple definitions for each release. The tool lives in /usr/libexec/firmwarecheckers/eficheck from memory and reports that your firmware is an issue and creates a dump of the firmware and gives an option of sending it to apple. I can not recall the url that was being used for querying apple but it is probably in everyones logs i suspect. The closest I could come to restoring the firmware was to reinstall from scratch and I am not sure that will fix the issue. Seems Apple no longer allows setting the firmware separately to match the release. I have found a few other sites that report the firmware for each release such as here but in reality I am wondering how every one else is dealing with the firmware updates and weekly errors if deciding not to go forward.

My Mojave 10.14.6 reported corrupted firmware after running up Catalina on an external drive as the valid Apple endorsed versions did not align. After 1 week of running that way my MAC failed completely and required a new logic board apparently....I'm not sure they were related but suspect that it could have been. Hence I'd rather make sure in future that the firmware and the MacOS align just to be on the safe side.
 
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When I want to test Catalina (did the same with Mojave), I first erased and formatted a partition on my external Samsung SSD, then did a clean, fresh installation of Catalina onto that partition, and finally migrated/copied needed files, folders, apps, settings, etc. from the internal SSD I started this process from. Never had an issue with either booting from that external partition, or from my internal SSD. Of course some of the apps I migrated were not yet compatible with the new OS, so could not either test them, or needed to download and install an update.

I use SuperDuper! for my backups, but if I used it to first clone my internal SSD (via SuperDuper!) onto the external partition of my SSD, then updated (not a clean, fresh installation) to the new OS, that could cause issues. As it is, whether testing or finally doing it, I always first Erase and Format the destination SSD/partition, then do a clean fresh installation of the new OS.
 
Sounds like a similar process that I used to use. However, the installation of catalina upgrades the firmware on the MAC and hence when returning to Mojave it now reports incorrect firmware versions. As the eficheck is on a weekly basis you need to wait poetntially up to a week to get a error about your firmware. 30 minutes after i got this message my MAC turned off and would refuse to turn back on.

About the only way I can see of potentially getting the firmware back to the correct version would be to always do a fresh clean nistall of the current internal operating system. Hopefully this would rewrite the firmware in that release rather than leaving the existing firmware. I'm asking that on the view of Apple that the catalina firmware is not compatible with Mojave and should obviously overwrite Catalina's. Makes the entire testing process painful but seems to be the only way to ensure that the hardware on the MAC is in the same state before installing on an external drive.

Each catalina update has had a EFI update as well by the looks.

Ideally I would like the state of the MAC to be the exact same as it was prior to running up a newer version on an external drive but seems the firmware updates now prevent this from occurring. Some one must have already done this and sorted out how to revert the MAC to the same state as it was prior to trying the newer OS?
 
tommiy said:
However, the installation of catalina upgrades the firmware on the MAC and hence when returning to Mojave it now reports incorrect firmware versions.
Click to expand...
You say it's reporting "incorrect" but I don't think that firmware is tied to macOS versioning. Firmware is firmware. Your machine should be able to boot to Mojave even after having Catalina installed. Can you post a picture of what it's reporting?
 
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Again, that has not happened to me, both with the testing of Catalina and (last year) Mojave. And I tested with at least 2 "iterations" of the new OS, ie, the 2 latest versions. Hence, with Catalina, I tested V10.15.2, and then V10.15.3. (I was waiting for Tech Tool Pro to finally release a version that was compatible with Catalina). So still not sure why you are having this issue.

If you want to get back to the original firmware, before you start any testing with the new OS, make a CCC clone of your current system (and insure it includes the installer file for the OS you are running). Then, if you have the firmware issue via the testing of the new Mac OS, you could boot to that "saved" CCC clone, run Disk Utility there to Erase and Format your internal drive/SSD, then migrate to the installer file for that "original" Mac OS, run it to do a clean, fresh installation of that OS onto your internal drive/SSD, and finally migrate/copy needed files, folders, apps, settings, etc. from that "saved" CCC clone (you'll be offered the opportunity to do that).

As it is, every week (on a Saturday), after running Onyx and Tech Tool Pro, I make 2 SuperDuper! backups for each of my Macs to 2 separate external SSDs. So, if I were to want and test a new OS between Saturdays, I already have the backup I need to do a restore, if needed. But again, I've never needed to do it.
 
Apple moved all firmware upgrades into the release and these are no longer separate. So installing Catalina upgrades the firmware to catalina firmware as part of the release. Each release of Catalina sees new firmware. This thread here has been tracking some of those version changes per release. As reported above, my mac died soon after this process so I can not show you what your asking because the logic board replaced by apple came with 10.15.1.

However, if you run 'eficheck --integrity-check' on your MAC and look at the console and filter for efi you will see the curl url that it uses with Apple to return the list of valid firmware for each release of MacOS. There is a thread some where on macrumors tracking the firmware changes with each release but I can not locate it just at the minute. There are also other sites such as here doing the same thing. Then while googling found this site that explains the exact same issue that I was seeing as a result of Catalina upgrading the firmware. At least one of these (the first I think) also states that the firmware upgrades Apple moved into each release and there is no option of changing the firmware other than the release.

While one could assume that an upgraded firmware will always be backwards compatible I'm not 100% convinced that this is the case with Apple. I supose you could use eficheck to save the firmware (one of its options) but whats the mechanism to put it back?
 
I don't think you can downgrade firmware, nor should you need to. That's why I'd like to see the error message you get when you attempt to boot Mojave.
 
As stated I can not provide because the logic board died. However its a nice popup box that provides the details thats stated by the website that I referenced. I'll see if I can google to find a picture for you instead of the test from the web site that verifies what I did get. I did actually send the report to apple and then 15 minutes later the MAC shut down and would no longer power on at all.

The thready tracking the firmware versions per OS release on Macrumors is here as well.

Unfortunately I'm not exactly willing to go off and try and reproduce on physical hardware while n lock down while there are web sites providing the same issues that I am explaining. However, I will see if I can manage to find a web site that has the GUI popup instead of text.
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Found a web site that displays the GUI that did pop up here. Now at the time I did track this down through console that the MAC was getting a list from Apple. There is also a list in the efi directory that lists compatibility against MACs as to what the current version of firmware being used is backwards compatible with. As this was all happening with 10.15.1 maybe apple forgot to update the lists (there is alot of entries in that list). I'm simply not sure.

Ideally I would like to be able to test a new release and be able to return to an installed release without incurring potential penalties by things like the firmware being incompatible. Saying firmware is always backwards compatible is not always the case unfortunately.
 
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Don't clone anything. Use a USB stick installer to perform a fresh install of the new OS version on your external drive. I do this with each new OS version that is released, and update it as new point versions come out. Been doing this for many versions. I never want to install a new OS on my main machine, rather wait it out and play with the new version on an external drive as it develops.
 
The issue is not the cloning but the installation of the new OS. Using a USB stick will result in the firmware of the MAC being upgraded the exact same as cloning and upgrading. There is no issue about the OS working and functioning but the changes to the hardware.
 
tommiy said:
Ideally I would like to be able to test a new release and be able to return to an installed release without incurring potential penalties by things like the firmware being incompatible. Saying firmware is always backwards compatible is not always the case unfortunately.
Click to expand...
Macs have never been restricted from running older, compatible versions. We’re that to ever change I’m certain Apple would inform us, or the world would have been talking about it before now. I think something else is going on with your machine, perhaps related to a failing logic board?
 
tommiy said:
The issue is not the cloning but the installation of the new OS. Using a USB stick will result in the firmware of the MAC being upgraded the exact same as cloning and upgrading. There is no issue about the OS working and functioning but the changes to the hardware.
Click to expand...

I run Mojave, and have Catalina installed on an external drive. I have not noticed any issues booting either version. MBP early 2015.
 
Thanks for the response.

Can you run eficheck manually from the lower version and see what you get? As noted at the start of the thread MACOS performs this check once per week and also remembers the answer to the response and never prompts you ever again. So if your in the habit of sending reports to apple then you will never see the error again but each week it will end a report to Apple.

Of course this also does not apply to recent T2 Macs that pdate the firmware differently. So 2017 probably is the last model.
 
chabig said:
The Mac's firmware isn't stored on the drive, so a backup and restore won't do anything. In fact, I don't think there is any way to downgrade firmware.
Click to expand...
Seems reasonable. Actually, I agree with what you said above:

"Firmware is firmware. Your machine should be able to boot to Mojave even after having Catalina installed. "

Again I state that when I still had High Sierra on my Mac, I installed Mojave (can't remember the exact version) on a formatted partition on my external Samsung 860 EVO 500 gig SSD. When I wanted to test Mojave, I would restart my Mac from that external partition, run my tests, then restart my Mac from its internal SSD containing Mojave. Same thing when I recently had Mojave installed on my Mac, and started testing Catalina (OS 10.15.2) via that same external partition. Again had no issues getting back to Mojave.
 
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