Build for ADB Prielli VV2220

I have an ADB Pirelli VV2220 router with the following device specifications:

  • CPU: Broadcom BCM63168 - 400 MHz
  • Subtarget : SMP
  • Package architecture : mips_mips32
  • Flash memory : 128 NAND
  • RAM memory : 128 MB
  • USB ports: 2

I have access to the CFE of the router and from the MTD layout it seems that this router has a second boot partition. So I'm trying to flash on this second partitions (I will call them slot 2 partitions) an image that is really similar to this router.

I found from the Table of Hardware this device: Comtrend VR-3032u
This device has really similar hardware to the ADB VV2220.

I report the MTD layout of my device that appears after the boot from slot 1 partitions(I created a hierarchical view to better understand ):

0x000000000000-0x000004000000 : "flash"
    0x000000000000-0x000000020000 : "CFE"
    0x000000020000-0x000001de0000 : "upgrade"
        0x000000020000-0x000000220000 : "bootfs_2"
        0x000000220000-0x000001de0000 : "rootfs_2"    
    0x000001f00000-0x000002100000 : "bootfs_1"
    0x000002100000-0x000003cc0000 : "rootfs_1"
    0x000003cc0000-0x000003ec0000 : "conf_fs"
    0x000003ec0000-0x000003f00000 : "conf_factory"
    0x000003f00000-0x000004000000 : "bbt"

As you can see there is a bootfs_2 and rootfs_2 partition that can be flashed. I tried to flash the content of the kernel and rootfs files contained in this image : by using the mtd write command in the following way:

mtd write /mnt/sda1/kernel bootfs_2
mtd write /mnt/sda1/root rootfs_2

The problem is that the bootfs_2 truncates the kernel at 2048kB . The kernel file of the Comtrent VR-3032u is instead 2432kB.

Is there a way to increase the bootfs_2 partition of 500kB and reduce the rootfs_2 of 500kB ?