How to kill mac - Downgrade Catalina to Mojave

Hello everyone.

I wanted downgrade Catalina to Mojave. What I've done:

1. I created Mojave bootable flash.

2. Enter to recovery mode and erase main disk.

3. Next restarted Mac to boot from the flash.

But system did't boot from flash. The system offered to "Starting Internet Recovery" from the WIFI. After the download progress reached 100%, the system showed icon with exclamation mark and message "apple.com/support -9000F". Now Mac does't boot from a any external drive, does't started in Recovery mode, I used ⌘-R and Option-⌘-R and Shift-Option-⌘-R and Options for select boot disk but Mac over and over again downloads something from the Internet and shows this error over and over again. I'm have a serious problem what should I do?

Replies

What model mac do you have?


Is it one with the T2 chip?

Yes, mackbook 15'' 2018

okay, have a look at:


https://www.macobserver.com/community/mgg-forum/2018-macbook-pro-trials-travails-and-caveats/


might give you a clue.

Have you figured it out, I have the exact same issue and have an appointment at Apple store until tomorrow.

I have no solution so far. I think I'll have to take the my mac to the service center

I took mine on Sunday to an Apple Store, they were going to attempt using the Apple Configurator to restore it, but if it failed, it would be sent to an Apple repair center. I looked the status online, and it looks like Apple repair center has it and working on it.

Since you do have a machine with a T2, do you have it set (through Recovery) to allow booting from an external disk? I hope I'm not (to you) stating the obvious, but I believe that is off by default.

My 2018 MacBook Pro was bricked by the downgrade attempt. It would not boot at all.


I contacted AppleCare and they are currently repairing it under warranty.


Prior to sending it off, we tried resetting the SMC and restoring the T2 firmware using the Apple Configurator 2 utility (as per the helpful link from luniacdevel)-- neither of which helped. The Configurator got pretty far along, then displayed an error message saying that T2 firmware could not be restored.


Once I get the MBP back, I'll stay on Mojave until Catalina is out of beta for a few weeks. I initialliy installed Catalina in order to try building a macOS version of my iPad app (which fails because several of the third party libraries I use will need to be recompiled first). Meanwhile, Xcode 11 beta runs fine with Mojave on my iMac Pro.

FYI, just got the MBP back from AppleCare. They replaced the logic board and touchID board.

I have exactly the same issue with my macbook pro 13" 2018.


I heard that this "-9000F' error is because Apple only have recovery server for released OS -- and of cause there is no server for Catalina. That means if I patient enough and wait after Catalina release in September, I should able to recover my macbook from brick by Network Recovery?


I have another macbook to finish my daily work so I'm not in a hurry, but just not sure to bring my bricked macbook to repair or just wait...

Same problem here. Cant do anything. should I wait for final release of catalina or what?

I got this error 9000f yesterday and fortunately I was able to fix it by booting into recovery mode using Cmd ⌘ + R and re-installing MacOS Catalina Beta.


What did I do?

I installed MacOS Caltalina on my 2018 MacBook Pro with T2 security chip, used it for about 2 weeks and then decided to go back to Mojave because some of the programs that I use for Web development and photo editing stoppped working correctly.


How I killed my MacBook Pro?

I did not read any downgrade procedure and just booted into recovery and used disk utilities to wipe the SSD. I didn't know that with T2 security chips, you have to enable external drive boot or else you almost brick your laptop.


How I was able to get rid of error 9000f?

  • With a freshly wiped SSD and no option to boot using any external drives, I decided to go with internet recovery by pressing Cmd + Shift + R which then asked me to connect to a WiFi, downloaded some stuff with the spinning globe on the screen, then straight away gave me the 9000f error.
  • I also tried using Cmd + Option + R to boot into recovery but got the same error again.
  • Then I tried using just Cmd ⌘ + R combination while booting up and somehow this time I was able to get to the installation screen that only allowed me to install Catalina Beta (which is okay instead of having a bricked laptop and a possible trip to the Apple store).
  • Bottomline, if you're getting error 9000f, the only way ressurect a bricked MacBook Pro with a T2 security chip is to re-install MacOS Catalina Beta.

If you're using the OS on your primary (or only) machine as your daily driver, yes. If you're a beta tester and this is a secondary machine, no. :-)

how to reinstall the macos catalina if i've got a 9000f? where to download the installer

thx

Same happened to me! I was updating macOS Catalina and always got stucked at 26 minutes. Was able to enter internet recovery mode through cmd + option + R (cmd + R gave me 9000F error), download again macOS Catalina beta, and try to reinstall it. Got again stucked at the 26 minutes. Anyone else?