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2012-2015 rMBP RAM upgrade interest?

Does anyone know if the Apple SMBIOS can be modified (EFI rom)? That is the last roadblock to overcome for this upgrade to become a reality. This is necessary because the DIMM banks do not have the traditional SPD chip that tells the BIOS it's speed, size, and density of the RAM.

From the factory, Apple uses four resistors to report to the BIOS the configured RAM type that is based on the chips that are soldered to the logic board. Obviously, none of the predetermined factory options will hold the 32GB size that we're after because the maximum the machines shipped with is 16GB.

The SMBIOS therefore needs updated to get around this artificial limitation.

@highvoltage12v Any ideas?
 
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Retina MacBook pros were only available in 8gb and 16gb configs. Why do you suppose it’s 4 resistors, or is it one per bank of chips or something?
 
profcutter said:
Retina MacBook pros were only available in 8gb and 16gb configs. Why do you suppose it’s 4 resistors, or is it one per bank of chips or something?
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The resistors (pullup/pulldown) tell the PCH the manufacturer of the RAM, the size, etc.

eyrHtXm.png

UYHAHPD.png

0y2vzOX.png
 
The locations in the ROM have been discovered after alot of digging in a hex editor! :D The thing left to do now is to calculate the correct DMI header and data for the 32GB of RAM and make a patched ROM file.

@highvoltage12v
 
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Quick update: this is totally possible if people are comfortable with the following things:

If Apple ships new ROM firmware in subsequent macOS updates, your computer may potentially and temporarily not boot until you patch the ROM again. The ROM edits are simply to insert/replace the existing ones that define the RAM SPD (serial presence detect) tables. It's nothing too elaborate by any means though :)

Due to the previously mentioned above item, you probably should not do this on your main and/or only computer you have since you will or may need a secondary computer and ROM programmer/cable to flash future ROM revisions.

Needless to say, you should keep your existing working ROM backed up at all times.

So, it is up to people to decide if all of the above is worth it or not to think about offering this as a mail-in logic board service and ROM flash.
 
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Would the reflash be something that would have to be updated itself with each os revision? How would the reflash work, would you need to have two machines connected?
 
profcutter said:
Would the reflash be something that would have to be updated itself with each os revision? How would the reflash work, would you need to have two machines connected?
Click to expand...

Apple doesn't always include EFI updates in each macOS minor update.

To flash the ROM, you can use something like this with it plugged into another computer. Should work on both mac and PC: https://www.amazon.com/gp/product/B07R5LPTYM/ref=ppx_yo_dt_b_asin_title_o00_s00?ie=UTF8&psc=1

Currently I have one on order to verify it.

There is a slight possibility of this message popping up on your computer if Apple detects the ROM doesn't match what they have on file, which is not a big deal since you can just dismiss it with 'Don't Send'.
eficheck-800x233.jpg
 
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Update: after many hours of research and firmware modifications, I've found that it is totally possible to upgrade the RAM on these machines, but there will always be caveats.

For the RAM upgrade to work, the EFI needs a module patched with the correct RAM SPD values, which means that when/if Apple updates the EFI in macOS updates, the machine has a high potential to temporarily become bricked because the Apple EFI will have the incorrect SPD values for what it thinks is the factory RAM configuration when it left the factory.
 
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If no side-effects, I would consider it. If 32GB can be a reality for my 15 inch 2015 dual graphics MBP, then I am on board with it.
 
I think what they’re saying is that for example, if you were to send them a MacBook Pro loaded with os 10.15.4, assuming they could figure out how to edit the EFI, you wouldn’t ever be able to update the system software without risk of bricking the system.
 
profcutter said:
I think what they’re saying is that for example, if you were to send them a MacBook Pro loaded with os 10.15.4, assuming they could figure out how to edit the EFI, you wouldn’t ever be able to update the system software without risk of bricking the system.
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agreed, the risk outweigh the reward imho.
 
Really, I will just hold on to the 2015 as it’s working great for me until the new PowerPC ones come out, I always mistake arm as a PPC. :)
 
Macbookprodude said:
Really, I will just hold on to the 2015 as it’s working great for me until the new PowerPC ones come out, I always mistake arm as a PPC. :)
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I have a PPC next to me. I use it as a charging stand for my iPhones and iPads.
[automerge]1587922162[/automerge]
Macbookprodude said:
Really, I will just hold on to the 2015 as it’s working great for me until the new PowerPC ones come out, I always mistake arm as a PPC. :)
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I have a PPC next to me. I use it as a charging stand for my iPhones and iPads. I have been trying to buy weight plates for my home gym. Maybe I can integrate the PowerMac into my exercise routine. Carrying it around the block should be a good workout.
 
You're stuck in an interesting spot, IMO.
Those with the skills and comfort level to pull the logic board to send your way, are also more likely to have relatively high(er) paying jobs, and with the release of the MBP16, might be inclined to update to that (which I just did, 2015 16GB 1TB to MBP16 32GB 2TB).

If the offer had come a year back - when I was struggling on the RAM to the point of having to do more on a work laptop... I would have jumped on it.

What about having the user remove the SSD but send the laptop to you for <the rest>? That might open up a few more people interested in it, as that's a fairly simple operation well within the skill set of anyone knowing the difference between a flat head and phillips screwdriver.. :)

What would total out the door cost look like?
 
wegster said:
You're stuck in an interesting spot, IMO.
Those with the skills and comfort level to pull the logic board to send your way, are also more likely to have relatively high(er) paying jobs, and with the release of the MBP16, might be inclined to update to that (which I just did, 2015 16GB 1TB to MBP16 32GB 2TB).

If the offer had come a year back - when I was struggling on the RAM to the point of having to do more on a work laptop... I would have jumped on it.

What about having the user remove the SSD but send the laptop to you for <the rest>? That might open up a few more people interested in it, as that's a fairly simple operation well within the skill set of anyone knowing the difference between a flat head and phillips screwdriver.. :)

What would total out the door cost look like?
Click to expand...

Originally it was decided to accept only logic boards, because there is a high chance that the rest of the machine, such as the screen, would be damaged in transit. It's too much hassle trying to get insurance claims through the shipping carriers.
 
But the issue of never getting to apply software updates is a serious one. Never getting to put in a security update if it includes a change to the EFI is kind of a dealbreaker for a lot of folks. For example, are you sure you’re happy sticking with 10.15.4 for as long as you have your current machine? It’s still pretty buggy.
 
Sounds good to me. No plan to upgrade past Mojave in any case on my 2013 rMBP as it will break a number of applications!
 
dhazeghi said:
Sounds good to me. No plan to upgrade past Mojave in any case on my 2013 rMBP as it will break a number of applications!
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Even if it wasn't a macOS update, a security update will occasionally include an EFI ROM update from Apple, which is the problem in itself, not macOS.
 
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