RAM corruption, possible eMMC corruption

[alnyan]

Hi everyone, 

I've been tinkering with my PinePhone for a while and noticed that eMMC is likely corrupt/being corrupted sometimes.
I tested that by downloading files from remote host and checking if their sha256sums match, which they didn't. Also rsync just fails to copy file quoting the same mismatch error.
After running PostmarketOS update using apk update && apk upgrade it just stopped unlocking (lock screen just reappears after a valid pin code), though apk verify said nothing about that.

I'd like to know if anyone else has/had that problem and if there're any workarounds to get eMMC stable.

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Forgot to mention: I also tried mounting tmpfs (which should be RAM-backed, I believe) and downloading my image there, but the result is the same — checksums mismatch

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Another addition: each time I run sha256sum on the same file, it yields a different checksum, so that's possibly RAM and not eMMC (updating thread title as well)

[zetabeta]

i don't know how easily to test ram memory, but i'm skilled enough to use command "dd" to test emmc mem. however, booting sdcard is necessary and tests still wipes data from emmc.

basic idea is to create 1 gigabyte of random bytes to write to disk and then read and verify it. knowledge of dd, /dev/urandom and sha256 is required.

at this point, test booting from sdcard first, and maybe proceed to test emmc.

[alnyan]

Tested that, looks like it's a RAM issue indeed. A quick fix for that is to use u-boot image with reduced DRAM frequency from https://forum.pine64.org/showthread.php?tid=9832. Hope the issue is resolved properly in the software/kernel though.

[JeremyWadsworth]

There are various ways that an eMMC could become corrupted. Some common causes of eMMC corruption include improper power supply, moisture and humidity, overheating, and shock. If any of these conditions are present, the data on the eMMC may be corrupted. If the corruption is due to improper power supply, try connecting the eMMC to a powered USB port instead of a DC power adapter.