Virtualbox on OS6 NAS

The update 6.2.3 broke VirtualBox due to the kernel upgrade.

So far I've experienced a couple of issues.
1. This file is corrupts (missing the end) from the Netgear download site -->ReadyNASOS_V6.2.3_WW_src.zip
2. When trying to install the kernel it fails

HOSTCC scripts/kconfig/conf.o /bin/sh: 1: scripts/basic/fixdep: Permission denied make[1]: *** [scripts/kconfig/conf.o] Error 126 make: *** [menuconfig] Error 2

I changed the permissions on scripts/basic/fixdep
then received

HOSTCC scripts/kconfig/conf.o *** Unable to find the ncurses libraries or the *** required header files. *** 'make menuconfig' requires the ncurses libraries. *** *** Install ncurses (ncurses-devel) and try again. *** make[1]: *** [scripts/kconfig/dochecklxdialog] Error 1 make: *** [menuconfig] Error 2

I decided to rollback to 6.2.2 and now

Reading package lists... Done Building dependency tree Reading state information... Done Some packages could not be installed. This may mean that you have requested an impossible situation or if you are using the unstable distribution that some required packages have not yet been created or been moved out of Incoming. The following information may help to resolve the situation: The following packages have unmet dependencies: build-essential : Depends: libc6-dev but it is not going to be installed or libc-dev Depends: g++ (>= 4:4.4.3) but it is not going to be installed E: Unable to correct problems, you have held broken packages.

So I seem to be left in no mans land, I haven't really had enough time to look into it in detail yet but this is . Anyone have some ideas?