Guess I’ll start from the beginning. I really wanted to test Raspberry Pi CM4 8GB for one of my projects (will add a link later).
As it’s very hard to find it available in stores (at the beginning of 2021), I had to do it myself.
As a donor, I took Raspberry Pi 4 8GB because the 8GB (64Gbit) chip is hard to find too (by a piece, I mean; if you need 1000x, then it’s possible to buy).
I managed to solder the memory from the Raspberry Pi 4 to CM4. And I decided to experiment a bit.
By the way, I used a cheap Lukey 702 soldering station. And a timer to follow temperature profiles (I have read about it on the internet). To be honest, this is my first reballing experience.
Unfortunately, 16GB chips are also not available by a piece. But I managed to buy 3GB chips.
Raspberry Pi successfully started with the chip MT53E768M32D4DT-053 AIT:E
And it shows me 3GB at the start:
Now I have a really unique Raspberry Pi 4 with 3GB of RAM.
System shows only 856MB of RAM available though. I even tried to solder the chip again, but the same:
So… You can call it a failure. But nevertheless, I think the whole project was a success. Memory passes all tests. I got a lot of experience. And perhaps with a firmware update, Raspberry will see 3GB, or I will solder 8GB or even 16GB chip one day.
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