You can and should only install this under flash. If it was previously installed, just uninstall it, and install the new version. The best way to proceed in my opinion, is the following. 1) boot to flash and install 36-5 upgrade, it will reboot 2) It will boot to flash again, now install bootmenu installer 3) Reboot 4) when it boots you will be able to boot to flash 36-5, or SD 30-2 (I am not sure however if the 36-5 upgrade will work run from SD?)