how to mount normal kernel rootfs not ubuntu rootfs

Autonomous Machines Jetson & Embedded Systems Jetson TX2
1

Hi,

There are some files that have information partition in Linux_for_Tegra folder

Linux_for_Tegra/bootloader/t186ref/cfg/flash_l4t_t186.xml
Linux_for_Tegra/p2771-0000.conf.common
Linux_for_Tegra/flash.sh

And i understood LNX partiton is kernel, APPFILE partiton is ubuntu rootfs.
I’m wonder how to mount normal kernel rootfs not ubuntu rootfs.

Plz let me know the answer.

Thanks,
Doohan93

2

Just FYI, originally the fastboot boot loader was used in earlier Tegra products. This used a dedicated partition for the kernel image. U-Boot does not…U-Boot finds the kernel on an ext4 partition “/boot” (named location via “/boot/extlinux/extlinux.conf”). Thus there is no “non-Ubuntu” kernel partition. (FYI, fastboot is still used in recovery mode, but only exists in RAM when doing that and goes away outside of recovery mode)

In the case of partitions containing binary data (such as in the old fastboot partition) there is no file system type, thus there is no mounting of it. One would have to make a copy with dd and then either use a binary hex editor or disassemble if it is executable.

The “APP” partition label in modern Jetsons is an ext4 partition including both rootfs and kernel. Labels are not particularly technical in nature other than some applications trying to find a correct partition by means of a label. There is also history of other Tegra hardware and earlier L4T releases involved, so you may find some labels are not used at all, or were more meaningful in the past, but not now.

Even among L4T release versions for the same hardware there will be differences. R24.2.1 and earlier will be quite different from later releases. If looking for information you’ll need to be specific about which release and what it is you actually want to do.

You will also find metadata at the start of a GPT partition scheme (you can call it “hidden”). This information prior to the first partition could be copied with dd, and then treated something like binary data with some executable code mixed in, but it isn’t necessarily made from just a single binary or a single program…it can be mixed content customized for the situation.