MBP 1,1-10,2 Downgrading a MacBook Pro running Catalina to High Sierra/Mojave?

[MacCraig Pro]

Hi All,

I have a mid-2012 MBP running 10.15 but has a HDD in it and I have spare SSD (128Gb) from a dead 2011 MBP that I'd like to put in it. The SSD has 10.13 on it and has quite a bit of software on it'd like to keep.

So question, if I put the SSD in the 2012 will it boot okay? Or will the later firmware cause issue? Can I essentially downgrade the OS in this way?

Many thanks!

Craig

 

[MBAir2010]

The used ssd wont ruin the MBP, but maybe not read since that is an older macbook
you could place that used ssd in a usb enclosure to make sure.

or you can get a external drive then Time Machine the 10.13 (high sierra?) then install the ssd,
then install Mojave over that.
remember that Catalina wont run 32 bit programs like adobe CS or older ones.

I have the same MacBook Pro an installed Catalina on a ssd drive were the dvd player was.
the other drive is Mojave.

I hoped this helped!

 

[MacCraig Pro]

Thanks! I will just have to try it and see what happens then!

 

[Chancha]

It will likely boot without issues. You maybe prompted to download MBP firmware update at some point but you can ignore that.

 

[Fishrrman]

OP:

I would do this (saves the trouble of swapping drives only to find out the replacement doesn't work):

Get one of these (they're cheap!):

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

SABRENT 2.5 Inch SATA to USB 3.0 Tool Free External Hard Drive Enclosure [Optimized for SSD, Support UASP SATA III] Black (EC-UASP)

www.amazon.com

Put the SSD into it -- it just snaps together.

Power down the 2012 MBP.
Connect the drive.

Now, hold down the option key CONTINUOUSLY, and press the power on button (keep holding down option).

When the startup manager appears, you should see two drives
- internal HDD
- external SSD (if it's recognized as being "bootable")

If you see the external drive, select it with the pointer and hit return.

Do you get "a good boot"?

If so, you know the drive is good to go.

NOW it's time to open up the MBP and "do the drive swap".

Take the old drive out and put that one into the enclosure.

Now you have an SSD-powered MBP -AND- an external drive that can be used either for backup or whatever else you might want to use it for...

 

[Audit13]

The MacBook should run with the SSD.

You may be prompted to update the OS which will also upgrade the firmware is a firmware update is needed.