MacBook Pro A1425 won't boot from USB, loads Ubuntu

ttimtucker wrote:

Unbricked! Took my MacBook to the Genius Bar. After 3 genius' puzzled on it for 10 minutes, they took it to the back room and disconnected/reconnected the battery. After that, all the unrecognized key sequences mentioned above worked, and I have successfully loaded Linux Mint from USB.

In hindsight it seems like an obvious solution.

Very unusual.

We appreciate you following up here & providing the ultimate solution.

ttimtucker wrote:

No matter what key sequence I use, the machine simply boots into Ubuntu. I have tried the following key sequences:

Select boot drive: Option key (tried left and right Option, also plugged in external keyboard and tried Alt)

So did this give you the Apple boot picker menu?

• Recovery: Command key

Recovery Mode is one of the following:

Command + R

Command + Option + R

Command + Option + Shift + R

• reset NVRAM: Option, Command, P, R for 10 seconds

There is no time involved for a PRAM Reset....in fact it really takes longer than 10 seconds. For the older Macs you just need to hold the PRAM Reset for at least two chimes....three if it lets you (I don't recall if early Retina models allowed three chimes). Many times the PRAM won't clear until at least the 2nd chime.

Any ideas on how I can boot from USB (or do anything other than boot Ubuntu)?

Wait to press & hold any special startup keys until immediately after hearing the startup chime. With some Macs, the special startup keys may be ignored if pressed too soon...same goes for pressing them too late. Timing is everything.

Try using a wired external USB keyboard in case the built-in keyboard is bad, but an external keyboard may not make any difference depending on how the built-in keyboard may have failed.

Disconnect all external devices in case one of them is causing a problem.

When pressing & holding the Option key, you should be shown the Option screen Apple boot picker menu. If you don't see this or a padlock on screen, then the system did not recognize the keys for some reason due to some sort of hardware failure (keyboard is first thought, MLB second, but could be Trackpad, or something else).

To boot a Mac from a USB drive, shut down the Mac, plug in the bootable USB, and turn it on while holding the Option (Alt) key until bootable volumes appear. Select the USB drive and press Enter.

If this does not work, maybe your Linux Mint drive is not bootable.

On Macs before 2018 models, the software that runs Recovery does not depend on ANY drive being available. Its code is pulled from ROM, and it creates cover 20 RAM disks to store its needed variables and files. Recovery runs, complete and self-contained, before any drive-loaded software is available.

The Startup manager (aka Boot-Picker) that runs when you hold the Alt/Option key at startup is even simpler. it also needs NO drives present to show a Gray (not blank) screen and proceed.

if that Mac can not do those, it is not working properly.

What may not be working properly is the snag-keys at startup.

Consider an SMC reset to club the initial state back into line.

It is entirely possible that a Graphics chip failure could keep anything from showing at startup. But entering Recovery should preclude continuing to boot up linux or macOS form any drive.

Have you successfully performed an NVRAM reset?

That would require using a keyboard that made the Mac respond with the feedback of chime-ing in response to the reset request, and continued to chime as long as those keys were held, recommended three or four cycles.

A1425 looks up to MacBook Pro 13-in Retina display from 2012 through 2013.

Tthe oldest shipped with 10.8.2 Mountain Lion, and can run up through MacOS 10.15 Catalina

It has Recovery in its ROM, accessible by holding Command-R. (both keys held down) at Startup.

Recovery will give you access to additional Utilities.

what version MacOS is on that USB drive?

Much more information is available, just ask.

The solid apple is loaded into RAM with the initial 'blob' of MacOS software, before the File system is activated.

if you are not loading MacOS, that solid Apple is not stored in the machine anywhere.

<< After 3 genius' puzzled on it for 10 minutes. >>

That was Not trivial problem!

It may seem obvious, but a successful NVRAM Reset (if it had been possible) would do the same -- clear all the variables in NVRAM.

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We are discouraged from suggesting "disconnect the battery" because novice users might read that suggestion and damage their computer or their person in attempting that.

ttimtucker wrote:

• I'm coming to the conclusion that this MacBook A1425 is bricked, because:

It boots into Ubuntu and is asking for a password, which I don't know (nor does the person who donated the machine to me).

• There is no key sequence which will prevent the MacBook from booting into Ubuntu

I think there is more to this story. It appears the person who donated the machine to you did not do this: https://support.apple.com/en-us/102773

I'm surprised that Apple support got it working for you.