Boot from CRAMFS partition on an emmc

[sankerspace]

Hello everyone,

Have someone worked extensively with cramfs rootfs?

I created an emmc.img file in buildroot 2020.11.1.

(several partitions with two same rootfs.cramfs partitions, but loading from one of them at a time)

I have created two rootfs partitions in that image file , which are both defined as

a CRAM Filesystem. (have zImage and device tree inside a rootfs.cramfs in the folder /boot)

My first problem is that i have no clue how to handle these two partition from U-boot (2016)

I have following commands:

   - cramfsls (should show directory from an image??) and

   - cramfsload   (have to set environment variable cramfsaddr, from where the cramfs is loaded plus offset )

Second problem is that with mmc part  the rootfs.cramfs partitions are not visible, but both defined as bootable.

But i know startadress and number of sectors from every partition

(got from fdisk -l on my host pc inspecting the emmc.img)

Maybe i have some missunderstanding how to handle that, but have someone an idea here?

Thanks for every help i get!!

PS: I dont want ramdisks as these are regularly used with cramfs

[sankerspace]

At first we made it that way, but cramfs has some attributes wie need for our project, and the most important reason we need is that our update files must be very small.

 So it has to be that way (and its not my decision), i hope you have some infos about handling cramfs from an emmc.

(even if it could be handled easier)

Nevertheless, thank you for your help!!

[b36401]

It is better to make FAT partition and place there zImage and rootfs as a files.