[FS#359] kirkwood: kernel does not recognize rootfs in ubi

[LEDE Bugs]

The following task has a new comment added:

FS#359 - kirkwood: kernel does not recognize rootfs in ubi
User who did this - Alberto Bursi (bobafetthotmail1)

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Sadly, that patch is unrelated (he changes the nand partition names of some kirkwood devices from "root" to "ubi"). My nand partitions already had the right names.

I just built an image with kernel outside of ubi (using same sources as I used for the bug report) and everything works fine. 

These are the partitions I have on flash now (before there was only ubi after the uboot stuff).

[    0.870019] 0x000000000000-0x000000100000 : "uboot"
[    0.876440] 0x000000100000-0x000000180000 : "uboot_env"
[    0.882786] 0x000000180000-0x000000680000 : "kernel"
[    0.888807] 0x000000680000-0x000008000000 : "ubi"

this is the part about ubi not failing like before and actually doing its job.

[    1.030586] UBI: auto-attach mtd3
[    1.033752] ubi0: attaching mtd3
[    1.040249] UBI: EOF marker found, PEBs from 12 will be erased
[    1.046376] ubi0: scanning is finished
[    1.081030] ubi0: volume 1 ("rootfs_data") re-sized from 9 to 938 LEBs
[    1.088278] ubi0: attached mtd3 (name "ubi", size 121 MiB)
[    1.093820] ubi0: PEB size: 131072 bytes (128 KiB), LEB size: 129024 bytes
[    1.100741] ubi0: min./max. I/O unit sizes: 2048/2048, sub-page size 512
[    1.107473] ubi0: VID header offset: 512 (aligned 512), data offset: 2048
[    1.114305] ubi0: good PEBs: 972, bad PEBs: 0, corrupted PEBs: 0
[    1.120348] ubi0: user volume: 2, internal volumes: 1, max. volumes count: 128
[    1.127600] ubi0: max/mean erase counter: 1/0, WL threshold: 4096, image sequence number: 120222938
[    1.136699] ubi0: available PEBs: 0, total reserved PEBs: 972, PEBs reserved for bad PEB handling: 20
[    1.146319] ubi0: background thread "ubi_bgt0d" started, PID 903
[    1.210154] block ubiblock0_0: created from ubi0:0(rootfs)
[    1.215682] ubiblock: device ubiblock0_0 (rootfs) set to be root filesystem


And I get to serial console afterwards.

So, there are either issues with the kernel patch that detects multiple partitions in ubi when there is also the kernel in it, or I did something wrong. 
I did copycat the goflexnet that is working fine here, so I'm a bit puzzled about this.
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More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=359#comment1124