Librerouter v1 booting from second partition broken

[Gio]

Hi!

librerouterOS used to be based on OpenWrt 19

librerouterOS is basically plain OpenWrt plus safe-upgrade,

safe-upgrade is a mechanism to flash an updated firmware to a second 
partition and mark it as testing, so if something goes wrong and user 
doesn't confirm everything is ok, after a while it reboot from the first 
partition, support for flashing a second partition and booting from 
there, to do this safe-upgrade basically does a bit of U-Boot trickery and

pass to kernel command line

mtdparts=spi0.0:256k(u-boot),64k(u-boot-env),7936k(firmware),7936k(fw2),128k(res),64k(ART)

to boot from first partition, while

mtdparts=spi0.0:256k(u-boot),64k(u-boot-env),7936k(fw1),7936k(firmware),128k(res),64k(ART)

when booting from second partition

OpenWrt 19 used to works perfectly with this trick, while with current 
development branch it boot perfectly from first partition but fails to 
boot from second :-/

AFAIU now mtdparts are passed via DTS so I have been fiddling with 
kernel options to avoid the kernel reading from there as of today I do this


     # Avoid MTD partition table being read from Device Tree 
safe-upgrade need
     # to change it depending if we need to boot fw1 or fw2 so it uses 
kernel
     # command line to pass partition table
     kconfig_unset CONFIG_MTD_OF_PARTS

     # Disable kernel command line being read from device tree which is 
mutually
     # exclusive with reading it from boot loader
     # CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER
     kconfig_unset CONFIG_MIPS_CMDLINE_FROM_DTB

     # safe-upgrade need kernel command line to be generated dinamically 
by the
     # boot loader (U-Boot) depending on which partition (either fw1 or 
fw2) it
     # need to boot
     kconfig_set CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER

and then pass the mtdparts to kernel command line via U-Boot, the result 
is that it keeps booting fine from first partition but it cannot find 
root partition when booting from second partition, apparently at some 
point sub-MTD-partitions get detected when booting from fw1 while they 
are not when booting from fw2


booting form first partition


[    0.334007] spi-nor spi0.0: w25q128 (16384 Kbytes)
[    0.338951] mtd: Found partition defined in DT for u-boot. Assigning 
OF node to support nvmem.
[    0.338964] mtd: Found partition defined in DT for u-boot-env. 
Assigning OF node to support nvmem.
[    0.347748] mtd: Found partition defined in DT for firmware. 
Assigning OF node to support nvmem.
[    0.356859] mtd: Found partition defined in DT for res. Assigning OF 
node to support nvmem.
[    0.365783] mtd: Found partition defined in DT for ART. Assigning OF 
node to support nvmem.
[    0.374263] 6 cmdlinepart partitions found on MTD device spi0.0
[    0.388733] Creating 6 MTD partitions on "spi0.0":
[    0.393595] 0x000000000000-0x000000040000 : "u-boot"
[    0.402035] 0x000000040000-0x000000050000 : "u-boot-env"
[    0.408366] 0x000000050000-0x000000810000 : "firmware"
[    0.416207] 2 uimage-fw partitions found on MTD device firmware
[    0.422228] Creating 2 MTD partitions on "firmware":
[    0.427307] 0x000000000000-0x000000240000 : "kernel"
[    0.433243] 0x000000240000-0x0000007c0000 : "rootfs"
[    0.440527] mtd: setting mtd4 (rootfs) as root device
[    0.445792] 1 squashfs-split partitions found on MTD device rootfs
[    0.452072] 0x000000690000-0x0000007c0000 : "rootfs_data"
[    0.458570] 0x000000810000-0x000000fd0000 : "fw2"
[    0.465664] 0x000000fd0000-0x000000ff0000 : "res"
[    0.471330] 0x000000ff0000-0x000001000000 : "ART"
[    0.869051] switch0: Atheros AR8337 rev. 2 switch registered on mdio.0



booting from the second


[    0.333444] spi-nor spi0.0: w25q128 (16384 Kbytes)
[    0.338391] mtd: Found partition defined in DT for u-boot. Assigning 
OF node to support nvmem.
[    0.338404] mtd: Found partition defined in DT for u-boot-env. 
Assigning OF node to support nvmem.
[    0.347192] mtd: Found partition defined in DT for res. Assigning OF 
node to support nvmem.
[    0.356297] mtd: Found partition defined in DT for ART. Assigning OF 
node to support nvmem.
[    0.364771] 6 cmdlinepart partitions found on MTD device spi0.0
[    0.379250] Creating 6 MTD partitions on "spi0.0":
[    0.384128] 0x000000000000-0x000000040000 : "u-boot"
[    0.392987] 0x000000040000-0x000000050000 : "u-boot-env"
[    0.400143] 0x000000050000-0x000000810000 : "fw1"
[    0.407352] 0x000000810000-0x000000fd0000 : "firmware"
[    0.414387] 0x000000fd0000-0x000000ff0000 : "res"
[    0.421421] 0x000000ff0000-0x000001000000 : "ART"
[    0.818598] switch0: Atheros AR8337 rev. 2 switch registered on mdio.0

.....


[    2.055622] /dev/root: Can't open blockdev
[    2.059807] VFS: Cannot open root device "(null)" or 
unknown-block(0,0): error -6
[    2.067440] Please append a correct "root=" boot option; here are the 
available partitions:
[    2.075921] 1f00             256 mtdblock0
[    2.075933]  (driver?)
[    2.082560] 1f01              64 mtdblock1
[    2.082568]  (driver?)
[    2.089212] 1f02            7936 mtdblock2
[    2.089222]  (driver?)
[    2.095856] 1f03            7936 mtdblock3
[    2.095866]  (driver?)
[    2.102490] 1f04             128 mtdblock4
[    2.102498]  (driver?)
[    2.109135] 1f05              64 mtdblock5
[    2.109144]  (driver?)
[    2.115779] Kernel panic - not syncing: VFS: Unable to mount root fs 
on unknown-block(0,0)
[    2.124157] Rebooting in 1 seconds..


AFAIU the code inside 400-mtd-mtdsplit-support.patch is working in the 
first case but not on the second, any suggestion?


Cheers

G10h4ck