Xperia E4g / default route via usb?

[RRIDDICC1]

Hi!

When I connect my E4g to my big box via a USB cable (while WLAN/Bluetooth is turned off), and then enable "USB tethering", and then configure the IPs via DHCP, it does not add a default route to that 192.168.42.129 IP.

My workaround is currently: I connect to an advertisement WLAN of the local cable TV provider, and then I add 192.168.42.129 as HTTP proxy to that dummy WLAN, and then I can surf the web via USB -- big box -- VDSL... But that just works for HTTP and HTTPS...

1. How can I run the command `ip route add default dev rndis0` successfully? When I do it via a terminal APK, it says that the operation is not permitted...

2. Why can't I just get a password protected root access on my E4g like on all my boxes? Am I missing a trick?

Thx.

Bye.