I installed nvidia-driver-535 on jetson-orin nano devkit(official dev board) and rebooted the Jetson. It is only showing NVIDIA Startup BIOS screen and monitor goes “NO SIGNAL”. But the jetson is still running, keyboard and mouse are working.
is there anyway I can get into the terminal from the start boot or any other way possible ? so that I can purge the installed nvidia-driver-535 and revert back to default to make it works as usual.
You must use the drivers from JetPack/SDK Manager. The driver you are looking at is for a discrete GPU (dGPU) on the PCI bus. The GPU of a Jetson is an integrated GPU (iGPU), and the drivers are incompatible (just having the PCI driver will probably cause a failure).
You should flash with JetPack/SDK Manager. Either the most recent L4T R35.x or 36.x (which uses mainline kernel) would work. See: https://developer.nvidia.com/linux-tegra
Incidentally, L4T is what actually gets flashed. This is Ubuntu plus NVIDIA drivers. JetPack/SDK Manager are just the front end to the actual flash software. It is SDKM which can automatically download and install the correct software for your L4T release.