mtdsplit differences between ar71xx linux 4.4 and 4.9?

[Christian Beier]

Hi guys,

I am currently in the process of porting a new device
(https://wiki.openwrt.org/inbox/engenius/engenius_emr3000v2) over to OpenWRT.

The issue I am facing is that mtdsplit works fine with kernel 4.4 

[    0.903158] m25p80 spi0.0: found s25fl256s1, expected m25p80
[    0.908907] m25p80 spi0.0: s25fl256s1 (32768 Kbytes)
[    0.913994] 7 cmdlinepart partitions found on MTD device spi0.0
[    0.919997] Creating 7 MTD partitions on "spi0.0":
[    0.924872] 0x000000000000-0x000000040000 : "u-boot"
[    0.931890] 0x000000040000-0x000000050000 : "u-boot-env"
[    0.938698] 0x000000050000-0x000000060000 : "art"
[    0.944885] 0x000000060000-0x0000001c0000 : "kernel"
[    0.951259] 0x0000001c0000-0x000001fb0000 : "rootfs"
[    0.957707] mtd: device 4 (rootfs) set to be root filesystem
[    0.963597] 1 squashfs-split partitions found on MTD device rootfs
[    0.969875] 0x000000440000-0x000001fb0000 : "rootfs_data"
[    0.976779] 0x000001fb0000-0x000002000000 : "config"
[    0.983224] 0x000000060000-0x000001fb0000 : "firmware"

but fails with this on 4.9:

[    0.951402] m25p80 spi0.0: found s25fl256s1, expected m25p80
[    0.957203] m25p80 spi0.0: s25fl256s1 (32768 Kbytes)
[    0.962266] 7 cmdlinepart partitions found on MTD device spi0.0
[    0.968277] Creating 7 MTD partitions on "spi0.0":
[    0.973141] 0x000000000000-0x000000040000 : "u-boot"
[    0.979849] 0x000000040000-0x000000050000 : "u-boot-env"
[    0.986630] 0x000000050000-0x000000060000 : "art"
[    0.992712] 0x000000060000-0x0000001c0000 : "kernel"
[    0.999136] 0x0000001c0000-0x000001fb0000 : "rootfs"
[    1.005551] mtd: device 4 (rootfs) set to be root filesystem
[    1.011311] mtdsplit: error occured while reading from "rootfs"
[    1.017348] 0x000001fb0000-0x000002000000 : "config"
[    1.023717] 0x000000060000-0x000001fb0000 : "firmware"

My patches are available at https://github.com/bk138/source/tree/emr3000-wip
and prefixed with "emr3k:".

Anyone any hints on what I might be missing?

Could it be that the way to generate a sysupgrade image has changed? Here's
what I'm using for emr3000  (and what works with 4.4):
https://github.com/bk138/source/blob/emr3000-wip/target/linux/ar71xx/image/senao.mk

Thanks in advance,

   Christian