7340: Stuck at fritzbox-labor-7340-19947

I loaded fritzbox-labor-7340-19947 firmware onto my 7340, but now I can't put other firmware on it.
AVM Recovery procedure fails :
Running FRITZ.Box_Fon_WLAN_7340.en-de-es-it-fr.04.90.recover-image.exe I results in endless message "searching for fritzbox at 192.168.178.1".

Also normal firmware update via WEB UI looks like it's working fine, but after reboot this labor firmware is still running.Firmware images tried:
FRITZ.Box_Fon_WLAN_7340.en-de-es-it-fr.99.04.90.image and also freetz image.


I hope to get some advice (can read german) before I mess up more stuff, for now I'm still using old 7170 using custom freetz

ruKernelTool didn't solve this, it also couldn't connect to adam2
However, reading it's documentation gave me a clue: Network link should be up pretty fast after power-on, but here it took about a minute.
I tried using LAN2 port on the fritzbox , and on first attempt, rukerneltool "Box-Informationen auslesen" was succesfull !

Then I played save and used avm restore program on LAN2, which also worked right away.

No on to freetzing the box.....