Problem to save Wireless connection after firmware upgrade to 6.01

Problem to save Wireless connection after firmware upgrade to 6.01

I'm experience problems with the wireless configuration after upgradeing the firmware to 6.01 no my X90L device. After disabling the writefilter, I connect to a wireless network, save the configuration, and reboot. When I log back on all the configuration is gone. 

Is there someone who can give me a tips how to fix this?

Thanks
Kjetil