OpenWrt: append-command does not work

The openWRT forum is down and there is info to ask questions here at LEDE forum.

I'm updating openWRT (master 030a23001b74ede5fa2e6070a8fb04f3feccfbbd) to router with MT7620 cpu. I'm able to build and flash my own firmware to the board and everything else seems to be ok but wifi is not working. I have narrowed the issue to 'append'-command. For example if I execute script I will get error from append-command.

root@OpenWrt:/# sh /lib/wifi/
/lib/wifi/ line 2: append: not found

The line 2 at is :
append DRIVERS "mac80211"

Thanks in advance for any support.

The error is expected, this script cannot be run standalone. It is indirectly sourced by /sbin/wifi, along with /lib/ which provides append().

OK, got it.

But the issue in my board is the same: wifi does not work. There is not /etc/config/wireless after board boots up. This error at startup is most likely related:

[   19.170370] ieee80211 phy0: rt2x00lib_request_eeprom_file: Info - Loading EEPROM data from 'soc_wmac.eeprom'.
[   19.190365] rt2800_wmac 10180000.wmac: Direct firmware load for soc_wmac.eeprom failed with error -2
[   19.208596] rt2800_wmac 10180000.wmac: Falling back to user helper
[   19.269238] firmware soc_wmac.eeprom: firmware_loading_store: map pages failed
[   19.283942] ieee80211 phy0: rt2x00lib_request_eeprom_file: Error - Failed to request EEPROM.
[   19.300845] rt2800_wmac: probe of 10180000.wmac failed with error -11

I'm installing firmware to a clean board so mtd2 (factory) is empty. I read from that flashing soc_wmac.eeprom to mtd2 was a solution to get rid of similar problem but my compilation does not produce such a file.