WiFi interface completely disappeared

I got a Metal 2SHPn which was working fine before i powered it off about 3 months agoe.
When i powered it up again (without changing anything on the hardware) today, i noticed that the WiFi interface is missing!
Tried several things to get it back… reboot, firmware upgrade to 7.6, reset to default config etc… nothing brang back the WiFi interface.
Can anybody please help?
wifi_missing.jpg

Found the issue.
The 1,2V step down regulator for the Atheros WiFi Chip was defect.