Ethernet fails 3% of the time

Ethernet on my Beaglebone Black is failing to come online about 3% of the time after power up. Attached are dmesg output from times when ethernet works (good_dmesg.txt) and the more rare times when it fails (bad_dmesg.txt). I’ve also attached full_bad_boot.txt which is the debug serial output from a boot that failed. Here is a diff of the two dmesgs, which I think might highlight the relevant areas:

< raid6: int32x1 xor() 140 MB/s

bad_dmesg.txt (9.24 KB)

good_dmesg.txt (9.13 KB)

full_bad_boot.txt (10.4 KB)

Oh, and I should note kernel is 4.12.12-yocto-standard.

Yes... Apply this patch, and it'll fix it 95% of the time...

Later boards (am43/etc) added a gpio to reset the phy, due to what was
seen on this design..


Thank you so much for the patch. This did seem to fix my problem, but then I found that it seems to work for some Beaglebone Blacks but not others. Even boards from the same manufacturer (but potentially different lots). What causes this issue? Is there something that would explain why the patch would fix the problem on some boards but not others? Are there some manufacturers that are likely to be better than others?