I got a GT-MT300N-V2 today and tried to hook it up to my Home WiFi in Repeater Mode and it seems to fail when using special characters in the WiFi Passphrase.
On my Home WiFi I have a Password set containing the characters , and ! and everytime I try to connect the Process will timeout and no Configuration is saved.
I set up a second WiFi with a PSK containing only lowercase characters and could connect on first try.
AVM Fritz!Box 6490 with current Firmware
1st SSID with Passphrase containing 16 Characters (lowercase and special)
2nd SSID with Passphrase containing 22 Characters (all lowercase)
GL-MT300N-V2 with current Firmware