Yes, the new firmware is in Japanese only.
I have tried to update my G300NH, but it doesn't work.....
I got a message that "invalid firmware".
They have updating the firmware recently as following but we don't have any update until now!!??
WZR-HP-G300NH_1.62_1.12 ? 18/08
WZR-HP-G300NH_1.62_1.09 ? 12/08
WZR-HP-G300NH_1.62_1.07 ? 24/07
WZR-HP-G300NH_1.62_1.04 ? 08/07
WZR-HP-G300NH_1.62_1.06 ? 08/07
WZR-HP-G300NH_1.62_1.03 ? 01/07
WZR-HP-G300NH 1.62 1.02 ? 29/06
Buffulo guys should do someting like Japan side.