Shared External UBI for rootfs_data

[momothefox]

Hi
I have this device i am trying to add support to.

Soc IPQ4018
Flash 1x 2MB SPI , 1x 128MB SPI-NAND
Uboot is locked so i cannot interact with it and i must follow it's configuration

Dual boot setup by passing bootpart=1 or 2 in cmdline
also stored in u-boot env

Press any key to stop autoboot:  0
Creating 1 MTD partitions on "nand1":
0x000000000000-0x000002000000 : "mtd=0"
UBI: attaching mtd2 to ubi0

Press any key to stop autoboot:  0
Creating 1 MTD partitions on "nand1":
0x000003000000-0x000005000000 : "mtd=1"
UBI: attaching mtd2 to ubi0

How to use rootfs_data volume in a separate ubi ?

UBI0 = has 2 volumes (kernel+ubi_rootfs)
UBI1 = Has 1 volume (rootfs_data)

[momothefox]

You cannot directly merge space or volumes between ubi0 and ubi1, because:

• Each ubiX (e.g., ubi0, ubi1) is a separate UBI instance attached to a separate MTD partition.
• UBI volumes are contained within one UBI device only; you cannot move LEBs (logical erase blocks) from one UBI device to another.

That what I have finally understand
so I had to do a workaround
I have been able to add a small rootfs_data inside my UBI and pass u-boot checks.

later i can mount the extra space

This is a solution because the request is wrong