I recorded JP 4.2.3 to SD card using Etcher. There are several partitions on this SD card - the main partition is in EXT format, other partitions in Windows and Ubuntu do not open. For example, SD card with Raspbian OS has a FAT partition with configuration files.
I also do not have the following folders, which are mentioned in the Tegra Linux Driver Package Development Guide:
Etcher tool only create partitions and write the OS image into SD-card,
if install the OS image with SDKmanager, your local host machine would also generate below two folders.
for example, ~/nvidia/nvidia_sdk/JetPack_4.2.2_Linux_GA_P3448/Linux_for_Tegra/
were you looking for boot configuration table (BCT)?
could you please share some details of your use-case.
Do I understand correctly that I cannot access the bootloader / and hardware / partitions without using SDKmanager?
What I want to do:
View and change the list of devices that are polled by the system at boot. During the boot process, an errors notification appears: imx219, iwlwifi, hdmi, thermal_zone and others. After loading, the system works fine, incl. display and wifi module.
Set display parameters manually. It seems that the system automatically determines the screen resolution at boot and restarts (the size of the Nvidia logo is changed during the boot process). This increases startup time.
I guess I need to create a separate topic about these errors and attach screenshots.
In theory you could do it without SDKmanager if you wrote your own replacement, however realistically, SDKmanager is required. It can run fine from within a VM if you don’t care about flashing devices directly.
You can modify the device tree from within the Linux_for_Tegra folder. Here is a thread on that:
… however it probably won’t get you much in terms of boot time. What will is disabling services. You can do this using the “systemctl” command with the “–root” option pointed to wherever your rootfs is (under Linux_for_Tegra) and create-jetson-nano-sd-card-image.sh (also in Linux_for_Tegra) can be used to create a bootable SD image after such modifications are made.