allwinner h3 ethernet corruption with active emmc?

help me to figure out what the issue is here

i have nanopi neo core board, which has emmc, awg ethernet and h3 soc

i had to hack a lot to get this up, including uboot (m1+) not meant for that board and fdt is also my own

for a while i ran current on it with just usb eth and everything was fine

when i started using awg eth, i experienced 10% of chance of network failure on init and rest of 90% showed stray corruption. dhclient told me packets are wrong size. ssh sometimes gave errors on mac. in failure mode, it gets so bad that switch port reports only errors from that port. like 50k errors. and no traffic is going or coming. although tcpdump shows something, it won't actually get to other side. on ping, it seems to reply but send out broken frames

note, i'm not really that good in any of this

it all gets fixed if i do ifconfig down/up cycle. well, apart from stray corruption

but how it fully gets fixed is when i wipe emmc clean and just use external sd card

then corruptions are gone, it boots up with network all the time

did i configure hw wrong with my uboot or fdt hacks?

is it broken hw? i was told test other boards but it's kind if difficult although i have more as they don't have headers on

if it's my hw and my hacks, how does it get fully fixed if i just leave emmc alone?

this is the only issue i've noticed, there are no data corruptions on emmc, etc. no panics no lockups. i only remember one time i noticed system had rebooted without reason but i wasn't there on uart to look it

so what's actually wrong here i'm wondering? h3 has good support i see. how those issues be fixed too? i get that emmc gets little usage compared to cards so maybe there's actual bug there?

i know it's kind of sd/mmc but with wider bus. i'm happy to try any patches someone might have. just don't expect me to fully get what they do