[LG G5 Guides, News, & Discussion] Mojo Dodo:
Okay, I continued trying and this is what I got so far:

In TWRP I did a complete wipe (Dalvik, System, Data, Internal Storage, Cache) + Format Data. Then I wiped misc again with dd if=/dev/zero (made a backup before).

Flashed stock (H85020s_00_OPEN_EU_OP_1114.kdz) with LGUP → I got a random MAC address (offset 6000 + 8000 in misc remains zeros)

Unlocked the bootloader and flashed TWRP → running ip link in TWRP shows another random MAC address. data/misc/wifi/config doesn't exist.

In TWRP wiped Dalvik, Sytem, Data, Cache, then flashed LineageOS + SuperSU

Reboot into LineageOS (WiFi is turned off) → MAC address 00:00:00:00:00:00 according to Lineage OS and ip link

cat data/misc/wifi/config
cur_etheraddr=00:00:00:00:00:00

Restart phone (with WiFi turned off) → MAC address 02:00:00:00:00:00 according to Lineage, random MAC according to ip link and

cat data/misc/wifi/config
cur_etheraddr=00:00:00:00:00:00

Turned WiFi on → MAC address in Lineage changes to 00:00:00:00:00:00 according to Lineage, ip link now also shows 0 instead of the random MAC and data/misc/wifi/config remains 0.

Turned WiFi off → removed config-file

h850:/ $ su
h850:/ # cat data/misc/wifi/config
cur_etheraddr=00:00:00:00:00:00
h850:/ # rm data/misc/wifi/config
h850:/ # cat data/misc/wifi/config
sush: cat: data/misc/wifi/config: No such file or directory

→ Turned WiFi on → Lineage gets a random MAC address and WiFi works:

while so, offset 6000 + 8000 in misc is still 0 and data/misc/wifi/config doesn't exist

Made an image of the misc-partition, inserted my desired (original) MAC at 6000 + 8000 with an Hex Editor and flashed the misc-partition (I did it with the phone booted, not in TWRP)

→ no difference in the phones behavior regarding the MAC address (I still get random IPs when turning WiFi on after phone booted)

So the situation for me with Lineage OS is this:

If I boot the phone with WiFi turned on the MAC address is 0 and data/misc/wifi/config shows 0 → WiFi doesn't work

If I turn WiFi off, delete data/misc/wifi/config and turn WiFi on again, I get a random MAC address (data/misc/wifi/config doesn't exist) → WiFi works

If I reboot the phone with WiFi turned off, ip link shows a random MAC. If I then write my desired MAC into config:

h850:/ # cat /sdcard/config > /data/misc/wifi/config

and turn WiFi on I get the MAC stored in config (which differs from the random MAC shown by ip link) → WiFi works

However, this is not permanent. After a reboot /data/misc/wifi/config always changes to 00:00:00:00:00:00 (even with WiFi turned off) which causes the phones MAC address to be 0.

This behaviour is not influenced at all by the values at offset 6000 + 8000 in the misc partition

So the only way to get WiFi working after each reboot is to delete/change /data/misc/wifi/config before turning WiFi on.

[MENTION=2684188]autoprime[/MENTION] do you have any additional suggestion?
[MENTION=4628223]totalnoob34[/MENTION] does your fota-partition (/dev/block/bootdevice/by-name/fota) contain any information? I've seen that I had also wiped that, so it's just 0 in my case. Some users report that's normal, but I'm sure about that.