2019 MacBook Pro Touch A1990 Can't Reinstall OS

It seems like the A1990 model is a MBPro 15" (2019).

Obviously the client was experiencing some issues with this laptop prior to having you wiping it. What type of issues did they report and did you check any system logs prior to the wipe (or retain the logs with the backup)?

I think your only option at this point is to perform a DFU Firmware Restore which resets the T2 security chip, system firmware, and internal SSD. Afterwards, you will need to boot into Internet Recovery Mode to reinstall macOS. Unfortunately you need access to another Mac currently running macOS 15.x Sequoia.

It can be very tricky/difficult to place a Mac into DFU mode. You must follow the instructions exactly since timing is critical and the laptop must be completely powered down when you start (tricky since there may not be any outward sign of its status). I personally like to press the Caps Lock key so its LED is lit. When the laptop is powered off, the LED will go out. I also like to have the Apple Configurator app open on the host Mac so you can see it report the status of the laptop as you attempt to place the broken Mac into DFU Mode.

How to revive or restore Mac firmware - Apple Support

You can also try an SMC Reset (the procedure is slightly different for the T2 Macs) and a PRAM Reset (best to hold it for two chimes if possible....with some Macs you may need to quickly release & re-press/hold the keys to get to the second chime). Doubt either one will help, but you are grasping at straws.

Have you tried running the Apple Diagnostics?

FYI, here is an Apple article regarding the -1008f error when booting into Internet Recovery Mode:

If your Mac starts up to error -1008F - Apple Support

There really isn't much more you can do since the USB-C Macs are very limited for troubleshooting options, especially the 2018+ models with the T2 security chips or the M-series Macs.

More than likely the Logic Board on this laptop has failed which is more common for the 2018-2020 Intel Macs with T2 chips than other models. I don't recommend anyone spend any money to repair any 2016-2020 Intel Macs for multiple reasons. The money spent on repairs is better put towards a new laptop.

I really hope you have educated the client on the absolute need to start frequent & regular backups of their computer and all external media (including the cloud) which contains important & unique data. There are a lot more new ways to permanently lose access to the data stored on the internal SSD of the recent Macs due to all of the hardware, software, and security changes. They got really lucky this time that you were able to save their data, next time it will probably be impossible.

Intel Macs from 2018 and later feature the T2 chip. The T2 chip creates a Secure Enclave and part of its firmware is in a special encrypted partition on the Drive.

If you ever COMPLETELY ERASE the drive, or its gets corrupted, a DFU Firmware restore is required, and it requires another VERY modern Mac to run this. HWTech pointed this out, but did not beat you over the head with it:

I think your only option at this point is to perform a DFU Firmware Restore which resets the T2 security chip, system firmware, and internal SSD. Afterwards, you will need to boot into Internet Recovery Mode to reinstall macOS. Unfortunately you need access to another Mac currently running macOS 15.x Sequoia.

the "Approved Method" for refreshing the drive on a Mac with T2 chip is to use 'Erase all content and settings':

Erase your Mac and reset it to factory settings - Apple Support

... the unspoken part is, "and keep the firmware intact"

Grant Bennet-Alder wrote:

Intel Macs from 2018 and later feature the T2 chip. The T2 chip creates a Secure Enclave and part of its firmware is in a special encrypted partition on the Drive.

That is the M-series Macs that keeps necessary & critical boot files stored on the internal SSD. Files that used to be embedded in the system firmware of the Intel Macs. Those files are even required to access the Startup Options screen for Recovery Mode for the M-series Macs. I'm not aware of any hidden files on the internal SSD of the T2 Macs which control booting.

However, if the entire internal SSD of a T2 Mac is erased, then it is not possible to boot from USB unless the T2 Mac was previously configured to allow booting from USB since the T2 security chip is no longer able to authenticate against any admin user accounts to modify those security settings after being erased. If booting from USB is unavailable and Internet Recovery Mode is having issues, then it leaves no other option than to perform a DFU Firmware Restore (it helps to fix Internet Recovery Mode issues)....and for Intel T2 Macs followed up by reinstalling macOS through Internet Recovery Mode (M-series Macs will automatically push a clean copy of macOS onto the internal SSD to restore those critical system file necessary for booting).

EdisonComputers wrote:

That's the weird thing - the customer didn't report any problems with the unit. They bought a newer system and wanted to pass this down the line to an employee, but (obviously) didn't want any of their personal information left on the system.

Most people don't notice anything until the system grinds to a halt or extremely slow crawl, or just crashes all the time with Kernel Panics.

FYI, you can ask the customer to bring their new laptop to you so that it can be used to perform the DFU Firmware Restore procedure. Their new Mac would be perfect since it would be running macOS 15.x Sequoia. You will need a USB only charging cable such as the one Apple provided to users with the 2016-2020 Intel Apple laptops (cannot use a USB-C Thunderbolt cable or a charging only cable....it must support USB protocols only). Yeah, why make anything simple & easy.

I had no issues with it, other than I couldn't run a TimeMachine backup because there was only ~350MB left free on the 1TB drive. I manually copied the Downloads folder to their external, then deleted it to free space. The only weird thing was that the DL folder was around 7GB - both before and after the copy - but when I deleted the folder contents, it only freed up 2GB on the drive. This still wasn't enough space for TM to run (which I don't understand at all, but 95% of the machines I work on are PC, so I'm not too concerned about that technicality).

FYI, on Macs using the APFS file system.....storage is very complicated.

If people are using TM or some third party backup software, then those apps tend to use the snapshot capability of the APFS file system to quickly save an instant image of the system. So if you delete data, that data may still reside within the hidden APFS snapshots until those snapshots are automatically deleted at some point in the future. For TM backups, that can be 24 to 48 hours, while third party backups may have their own defaults that may sometimes be configurable by the user.

Also, if people copy items from one location to another on the same APFS volume, then the "copy" will only be a small link to the original physical copy of the data. This is meant to make for fast "copies" and to save space and to minimize wear on an SSD which has a limited amount of lifetime writes available. So if data has been "copied", then all copies & links to that physical data must be deleted before you will see any change in the Free storage space, but remember you still have to contend with APFS snapshots.

Another thing to be aware of when working with Macs is that the "Available" storage space value shown everywhere in macOS is very misleading & should be ignored. The only storage value that is important is the Free space value shown only in Disk Utility and the Apple System Profiler (aka System Information). With macOS Free is not synonymous with Available. In fact even the "Used" storage value can be misleading depending on how the Mac is used & configured (it may show more "Used" space than the physical storage can hold....part of it can be due to the "copy" feature I mentioned earlier).

Free space = Available space - Purgeable space

Purgeable space is storage that macOS will automatically delete at some unknown time in the future. Apple says it will be released once space is needed, but from reading this forum that is not the case in the real world. APFS snapshots are one example which hold deleted data that will be "purged" once the snapshot is finally deleted. There are other things too.

Continued....

I spoke with an associate that has a business that only does board-level repairs on Mac laptops - I'm going to shamelessly throw his contact info out here, since I'm so happy I found anyone with any knowledge about that level of repair, let alone one that I've had a 100% success rate with over quite a few different machines with different issues:

I'm sure I don't have to explain how VERY RARE it is that you can find that level of knowledge in any area today.

Anyway, he came up with a very similar response - basically that there *has* to be a hardware issue somewhere, even though there were no outward signs of an issue. Again, my work is 95% PC, so I figured that I just didn't know something about MBP's of that generation, but both responses I got are pretty much in agreement.

Yes, it is very rare to find people with such knowledge & skills these days. And a good reputation.

FYI, with the 2018+ Macs it has become very difficult to perform board level repairs anymore on a Mac. Plus some of the hardware designs just make it more likely for a failure to occur & more difficult to repair. And with the M-series Macs I understand it is nearly impossible to perform board level repairs because Apple actively blocks access to the necessary chips. And even scavenging used/broken boards is even harder as well. Not very green if you ask me.

Obviously neither are OEM Apple adapters. It couldn't be that, right???!!!

Doubtful. More likely bad USB-C ports...I find they often become liquid damaged (cannot easily see to confirm for sure unless the I/O Board is physically removed from the system). Usually the laptop won't run on the charger or charge at all, but there have been some exceptions (just had one the other day).

Depending on what the customer decides, my plan now is to send the machine to Steven for a full diagnostic. I'll post the outcome whatever way it goes - I feel like they're either going to can the machine or bring it to the Apple store - but maybe not. I'm not going to make a penny on this thing, but at this point I'm really more interested in getting a definitive answer on this versus a paycheck lol.

Even if Steven can fix it, I don't think it is worthwhile due to the high failure rate of the Logic Board for this specific laptop. It is likely to fail again and not because of anything Steven may do to it.

Thanks for clarifying the WHY of getting in trouble by erasing the entire drive on a T2 chip intel Mac.

It is convoluted in different ways than I thought.

I stand corrected.