Hi, I use OpenWRT since more than a year happily on my Netgear DGN3500B.
But the sysupgrade to 19.07.1 (from 19.7.0) causes the first time some troubles, as the WIFI interface doesn't get the physical connection:
[ 28.591855] ath: phy0: Unable to initialize hardware; initialization status: -5
[ 28.597765] ath9k 0000:00:0e.0: Failed to initialize device
[ 28.603379] ath9k: probe of 0000:00:0e.0 failed with error -5
and sysmessage
Wed Jan 29 17:06:33 2020 kern.info kernel: [ 0.753302] libphy: rtl8366rb: probed
Wed Jan 29 17:06:33 2020 kern.info kernel: [ 0.756907] libphy: Fixed MDIO Bus: probed
Wed Jan 29 17:06:33 2020 kern.info kernel: [ 0.762339] libphy: ltq_mii: probed
Wed Jan 29 17:06:33 2020 kern.err kernel: [ 0.764388] ltq_etop 1e180000.etop eth0 (uninitialized): no PHY found
Wed Jan 29 17:06:33 2020 kern.warn kernel: [ 0.770942] etop: mdio probe failed
...
Wed Jan 29 17:06:44 2020 kern.warn kernel: [ 28.525448] PCI: Enabling device 0000:00:0e.0 (0000 -> 0002)
Wed Jan 29 17:06:44 2020 kern.err kernel: [ 28.591855] ath: phy0: Unable to initialize hardware; initialization status: -5
Wed Jan 29 17:06:44 2020 kern.err kernel: [ 28.597765] ath9k 0000:00:0e.0: Failed to initialize device
Wed Jan 29 17:06:44 2020 kern.warn kernel: [ 28.603379] ath9k: probe of 0000:00:0e.0 failed with error -5
...
Wed Jan 29 17:06:56 2020 daemon.notice netifd: radio0 (1128): Could not find PHY for device 'radio0'
I didn't found any solution (reboot, re-enabling device / interface / wifi). Only a downgrade to 19.7.0 got my wifi back 
Any ideas how I can get it back on the recent version of OpenWRT?
My infos
NAME="OpenWrt"
VERSION="19.07.1"
ID="openwrt"
ID_LIKE="lede openwrt"
PRETTY_NAME="OpenWrt 19.07.1"
VERSION_ID="19.07.1"
HOME_URL="https://openwrt.org/"
BUG_URL="https://bugs.openwrt.org/"
SUPPORT_URL="https://forum.openwrt.org/"
BUILD_ID="r10911-c155900f66"
OPENWRT_BOARD="lantiq/xway"
OPENWRT_ARCH="mips_24kc"
OPENWRT_TAINTS=""
OPENWRT_DEVICE_MANUFACTURER="OpenWrt"
OPENWRT_DEVICE_MANUFACTURER_URL="https://openwrt.org/"
OPENWRT_DEVICE_PRODUCT="Generic"
OPENWRT_DEVICE_REVISION="v0"
OPENWRT_RELEASE="OpenWrt 19.07.1 r10911-c155900f66"