having a non-nav unit means that you will not be able to install the SD patch (nor the toolbox), as the installation method exploits a vulnerability of the installation process and is based on the nav-only package.
If you have the toolbox, it means that someone used the eMMC or USBHSD method - direct access to system memory. Sad that the GEM was not updated. This means that toolbox is not able to execute any of the scripts (that's why you need to reboot the unit).
Since you don't know exactly what was done with the unit, you might also check if the telnet or FPT connections were enabled. If yes - you are in and you will be able to access the filesystem via network connection (MIB WiFi or DLink) to change some stuff.
If you have the toolbox, it means that someone used the eMMC or USBHSD method - direct access to system memory. Sad that the GEM was not updated. This means that toolbox is not able to execute any of the scripts (that's why you need to reboot the unit).
Since you don't know exactly what was done with the unit, you might also check if the telnet or FPT connections were enabled. If yes - you are in and you will be able to access the filesystem via network connection (MIB WiFi or DLink) to change some stuff.