This remember me another post...
Version 18.06 erased CAL_DATA partition of three of my routers. I don't know if your router had this partition, but if you don't get the calibration data, your router is bricked. Try to flash original stock firmware, maybe the CAL_DATA partition back, and then flash 17.01.04.
I have 2 ac-lite router.
Router A has 17.01.4. If I upgrade this to 18.06.1 wifi disappears. When I go back to 17.01.4 wifi is back again.
Router B has stock ubnt firmware. If I upgrade it to 18.06.1 wifi works well.
I restored the original ubnt firmware on Router A then upgraded directly to 18.06 and now wifi works on this router as well.
same problem in 18.06 (don't know previous versions). I think is the same device [1]
upgrading to snapshot (2019-10-25) solved the problem and wifi works as expected. I think/hope wifi will work in next stable (maybe 19.07)
[1]
root@OpenWrt:~# cat /etc/board.json
{
"model": {
"id": "arcadyan,arv7518pw",
"name": "Astoria Networks ARV7518PW"
},
my wifi broke completely with openwrt and original d-link after flashing - AR9287 ( D-Link DSL-2740B):
solution:
go back to d-link http://files.dlink.com.au/products/DSL-2740B/REV_F1/Firmware/Firmware_v2.04_(26-07-2012)/DSL2740B_F1_AU_2.04_07262012.bin
and you have working wifi again, and you can use it in openwrt.
somehow openwrt deletes important flash memory in 2nd update.
btw. i have eu Version, no Australia. but works also.