iMac 2012 upgrades and CCC questions

le.bouch

macrumors regular
Original poster
Aug 3, 2010
159
66
Having tinkered inside my 2012 i5 27” iMac before (I fitted a blade SSD and new 3TB HDD), I plan to do one last upgrade to squeeze another couple of years out of it.

I will upgrade to an i7 CPU, 2013 AC wireless card and swap the HDD for a 2TB SSD.
I plan to do this in the next few days.

Time Machine has become more and more unreliable for me over the last few Mac OS upgrades so I’ve started using Carbon Copy Cloner - that said, I’ve never actually had to recover from it or otherwise use it in anger.

Can I check one thing before I proceed?

With my current configuration still intact, I plan to use CCC to clone my existing boot drive to my new SSD in a caddy.

Can I then simply install the SSD internally (after the CPU etc is upgraded) and expect my iMac to boot as before?

Any gotchas I’ve missed?

Thanks for any help at all.
 

PaulD-UK

macrumors regular
Oct 23, 2009
116
9
"I plan to use CCC to clone my existing boot drive to my new SSD in a caddy."

You need to configure CCC to clone the Recovery Partition(s) as well as the main Mac OS partition, so as to preserve the Recovery ability.
I read one guide which suggested doing an online new install of (your current) Mac OS from Apple - this will correctly configure the Recovery section of the SSD, then once that is working you can do a simpler erase/clone of just the main Mac OS partition from your old HD.
 

Fishrrman

macrumors Core
Feb 20, 2009
19,390
6,702
The blade SSD and HDD are not "fused", are they?

If the answer is "no", then the procedure you outlined in your OP should work fine.

You can use the caddy to "prep and test" the new SSD before you install it.
 

le.bouch

macrumors regular
Original poster
Aug 3, 2010
159
66
The blade SSD and HDD are not "fused", are they?

If the answer is "no", then the procedure you outlined in your OP should work fine.

You can use the caddy to "prep and test" the new SSD before you install it.
Thanks. Actually they are Fused but my understanding is:

a) It doesn't matter to CCC if the clone source is a Fusion (existing 256GB Blade and 3TB HDD) and the destination (new 2TB SSD) is not.
b) Once I remove the internal HDD that will 'break' the Fusion setup.
c) I can leave the Blade SSD physically in situ and wipe it later.
d) The iMac will boot from the newly-installed clone SSD.

Happy to be told otherwise. Everyday's a school-day and all that :)
- - Post merged: - -

"I plan to use CCC to clone my existing boot drive to my new SSD in a caddy."

You need to configure CCC to clone the Recovery Partition(s) as well as the main Mac OS partition, so as to preserve the Recovery ability.
I read one guide which suggested doing an online new install of (your current) Mac OS from Apple - this will correctly configure the Recovery section of the SSD, then once that is working you can do a simpler erase/clone of just the main Mac OS partition from your old HD.
Have done some reading on V5.15 of CCC - it suggests (I think) that since APFS CCC now takes care of the Recovery Partition? Am I reading this right?

Screenshot 2020-02-16 at 15.38.20.png
 
Last edited:

Fishrrman

macrumors Core
Feb 20, 2009
19,390
6,702
CCC will clone a "fusion" drive to a non-fusion drive, no problems.
It can even clone APFS to HFS+, no problems.

So... clone the fusion drive to a backup, it will be fine, a recovery partition should be created, too.

Remember -- once you remove "one side" of the internal fusion drive, the data is lost forever and your only "pathway back" is to restore from the backup.

But a final thought:
If BOTH drives will now be SSDs, there's really no need to "fuse" them.
Just let them live inside as "standalone drives".
 

le.bouch

macrumors regular
Original poster
Aug 3, 2010
159
66
CCC will clone a "fusion" drive to a non-fusion drive, no problems.
It can even clone APFS to HFS+, no problems.

So... clone the fusion drive to a backup, it will be fine, a recovery partition should be created, too.

Remember -- once you remove "one side" of the internal fusion drive, the data is lost forever and your only "pathway back" is to restore from the backup.

But a final thought:
If BOTH drives will now be SSDs, there's really no need to "fuse" them.
Just let them live inside as "standalone drives".
Thanks again. Yes, that's my plan - I'll keep both SSD's separate, although I won't wipe the Blade until I know everything's working OK. That way, if I mess up I can just put the original 3TB HDD back in and it should 'fuse' with the Blade again. That's the theory anyway, lol. I hope to do all this in the next 7 days so I'll post my results here, just for completeness.
 

le.bouch

macrumors regular
Original poster
Aug 3, 2010
159
66
So it’s done, and did work as I hoped. Thanks to those who offered advice.

Using CCC I cloned my existing Fusion Drive (internal 3TB HDD and blade 256GB SSD) to a new Samsung 860 2TB SSD in a temp USB caddy. I then booted from that to ensure everything was ok.
I opened the iMac and swapped out the HDD for the new SSD, in a 3.5” to 2.5” bracket. I left the blade SSD in situ.
I swapped the i5 2.9 cpu for an i7 3.4 3770 (not K or S) cpu. I swapped the wireless card for an Apple BCM94360CD card - this adds AC wireless to the iMac.
I had read (sorry - can’t find the source again) that since one of the later Mac OS versions it was no longer necessary to include the OWC thermal sensor cable when you replace the OEM HDD with an SSD. As an experiment I removed my OWC cable - so far no max fan speed problems.

Upon startup the iMac tried to boot from the previous Fusion setup, I guess because half of it (the blade SSD) was still in situ. That obviously failed but once instructed to boot from the new SSD it worked perfectly. I then wiped and reformatted the blade to give me back 256GB storage.

Not the most adventurous tinkering, I know, but it may help someone who’s considering squeezing some more life out of their 2012 iMac 27” i5.
 
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