Default Nexus 5 (hammerhead) - Tethering broken?

Hi,

Since about 4.4.3 (possibly 4.4.2?) wifi-tethering broke.
logcat says:

Code:
D/AFWall  ( 3615): OS reported AP state change: 11 -> 12
D/AFWall  ( 3615): isWifiApEnabled is false
E/SoftapController( 1320): Cannot update "/data/misc/wifi/hostapd.conf": Permission denied
E/WifiStateMachine( 1837): Exception in softap start java.lang.IllegalStateException: command '79 softap set wlan0 AndroidAP broadcast 6 wpa2-psk [scrubbed]' failed with '400 79 SoftAP command has failed'
E/SoftapController( 1320): SoftAP is not running
D/SoftapController( 1320): Softap fwReload - Ok
D/SoftapController( 1320): Softap fwReload - Ok
D/dalvikvm( 3615): GC_CONCURRENT freed 390K, 11% free 12321K/13772K, paused 4ms+1ms, total 18ms
I/AFWall  ( 3615): Now assuming 3G connection (non-tethered)
E/SoftapController( 1320): Cannot update "/data/misc/wifi/hostapd.conf": Permission denied
E/WifiStateMachine( 1837): Exception in softap re-start java.lang.IllegalStateException: command '83 softap set wlan0 AndroidAP broadcast 6 wpa2-psk [scrubbed]' failed with '400 83 SoftAP command has failed'
D/AFWall  ( 3615): OS reported AP state change: 12 -> 14
D/AFWall  ( 3615): isWifiApEnabled is false
This bug is reported on code.google.com but the only suggested solution is deleting /data/misc/wifi and reboot which didn't work for me.
I even chmoded 777 /data/misc/wifi and hostapd.conf but without any success.

I'm running a very recent nightly (a few days old).

Any thoughts?

Thank you.