Say I have a soldering iron and want to replace the RAM module on the Librem 5 with a higher capacity one. How would it work? Would it need a software change, or new wiring? Or would it be a matter of accurate soldering, and possibly even getting to impossible-to-reach places on a surface mount? I know very little about how the hardware is initialised in ARM.
The ram is probably easy to reach on the board. A soldering iron will most likely be useless as i believe that the ram is a BGA (ball grid array) chip which has all its contacts on the bottom side. You would need a special heat gun and a solder ball mask fiting the bga layout of the ram chip to replace it. You can find youtube videos on how to replace bga chips.
So it’s on the advanced side of “soldering”. especially as you cant see if all solder balls have ben applied correctly. So you have to know you done it right or might destroy your chips.
So not impossible but hard i would say.
The second part is if a bigger chips as 3gb can be used as drop in replacement. That would require a detail look into the i.mx8 documentation.
Additionally purism has done some work around for the ddr4 training. So this might be tailored to the ram size and might also need adoption.
So all in all i would guess it is more on the impossible side. But don’t let me stop you. Sounds like a nice challenge. But i think you should definitely have the pocket money for a spare librem 5.
Ah and i have seen someone upgrading the storage of an iphone. Which is the same complexity on the soldering part.
Same guy how added a headphone jack to a newer iphone. An he learned the soldering things while doing it. But i think he bought like 5 scrap iphone pcbs to train on.
i would focus my attention on lowering the resource usage of the OS before considering adding more HARDWARE resources especially if i’m not up for it.
the first is also beneficial for most people while the second only benefits the person who does the hardware “upgrade”
I think there’s a high chance of failure if you attempt to solder on a new BGA chip without any experience or practise runs. It’s certainly not an impossible job, but it will require an investment of time and resources that might not be reasonable if you don’t plan to use the acquired skill for anything else. And even professional PCB rework technicians don’t have a 100% success rate.