Hello,
can you help me please.
i have a Router with Openwrt and BCM6756 and it run well.
Yes i know this is very special.
I call it Router A.

2x Router B the little brother of Router A:
I flash the Image from Router A to Router B.
Router B start the bootloader dont load the image from Nand.
And no Network and no usb
After i change the Boardid i have Network Access and usb
But i chacnge it the Bootloader to test say: Need Hard Reset. I think one die.

I have SSH and Serial Access to Router A and B.
I have MTD and Nanddump with openwrt from Router A.

Can you Help me please:
Plan 1: Router B bootloader and Router A Openwrt.
Plan 2: Router B boot from Nanddump?
Plan 3: I write the mtd (only image mtd) from Router A to Router B?
Plan 4: Usb boot Router B with Nanddump from router A.

Thankyou :-)



Edited 3 time(s). Last edit at 11/16/2025 02:08PM by Quantummaster.

Let me move this thread to the Rescue System section. It's where all OpenWrt discussions are.

-bodhi
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Thankyou sir.

One Router die, i change the boardid and this is very important for BCM.
The Ram Timing ist fault.

http://skaya.enix.org/wiki/FirmwareFormat

But my Goal is the Router B with Openwrt :-) from Router A.
If i flash the only mtd2 and it faile i can recover with cfe?



Edited 1 time(s). Last edit at 11/16/2025 03:36PM by Quantummaster.

> But my Goal is the Router B with Openwrt :-) from
> Router A.
> If i flash the only mtd2 and it faile i can
> recover with cfe?

I don't have any idea about this. These routers have Broadcom SoCs. If there are enough differences between A and B SoCs then it will not boot the kernel. Does OpenWrt have installation instruction for both?

-bodhi
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I dump from the Router A MTD

mtd0: 10000000 00020000 ""
mtd1: 00200000 00020000 "loader"
mtd2: 0fd00000 00020000 "image"

And now i need the Adress or command for Nandwrite in Openwrt for mtd2
I read your Tutorial and very great work and many thanks to share it :-)

But it is late :-) in Germany.

I see tftp boot, fatupdate mmc but i dont understand the Adress.

And can tftp boot from mtd2 or mtd0 without flash my uboot. (only load in Ram)

Openwrt and Broadcom SoCs are not good Friends.
I want this Openwrt on the other router, i need the spezial features.

The Router have the same soc, size of ram and nand.
The Bootloader is different.
I can flash the complete image with cfe, but the bootloader dont boot the openwrt i must change the env.
But last i edit the env i kill it.

I must change this, i think.

fdtcontroladdr=1dd66b48
mtdparts=spi1.0:2097152(loader),264241152@2097152(image)

I look later in this thread, and thank you for your time and have a nice time



Edited 8 time(s). Last edit at 11/16/2025 06:43PM by Quantummaster.

> The Bootloader is different.
> I can flash the complete image with cfe, but the
> bootloader dont boot the openwrt i must change the
> env.

OK, so you have envs listing for both A and B? please post tthem here.

And when you play with the envs, don't save them. You only need to save them permanently after you are satisfied that you can boot into OpenWrt.

-bodhi
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Thanks for the heads-up.

I vaguely remember changing the values ​​and it working, but I must have saved them out of stupidity.

Because I thought it wouldn't accept them otherwise.

Learned something new.

I sent you a message before I post the environment values.

Router A:

IMAGE=NAND:2M,1024M
bootcmd=printenv;run once;sdk boot_img
bootdelay=3
dhd0=11
env_boot_magic=16384@0x40000,0xad000
ethact=systemport@0x80490000
fdtaddr=7f74000
fdtcontroladdr=dd69548
filesize=4
ipaddr=192.168.1.1
mtddevname=loader
mtddevnum=0
mtdids=nand0=brcmnand.0
mtdparts=brcmnand.0:2097152(loader),265289728@2097152(image)
nand_erasesize=20000
nand_oobsize=6c
nand_writesize=800
netmask=255.255.255.0
nummacaddrs=10
once=true
partition=nand0,0 rootfs_opts=ubi.block=0,rootfs2 root=/dev/ubiblock0_6 ro ubi.mtd=image rootfstype=squashfs
stderr=serial0
stdin=serial0
stdout=serial0

Router B:

IMAGE=NAND:2M,254M,255M 
bootcmd=printenv;run once;sdk boot_img 
bootdelay=3 
dhd0=0 
env_boot_magic=16384@0x40000,0xad000 
ethact=systemport@0x80490000 
fdtaddr=7f74000 
fdtcontroladdr=1dd66b48 
filesize=4 
ipaddr=192.168.1.1 
mtddevname=loader 
mtddevnum=0 
mtdids=nand0=spi1.0 
mtdoops=crashlog 
mtdparts=spi1.0:2097152(loader),264241152@2097152(image),524288@266338304(crashlog) 
netmask=255.255.255.0 
nummacaddrs=10 
once=true 
partition=nand0,0 rootfs_opts=root=/dev/ubiblock0_4 ubi.mtd=image ubi.block=0,4 rootfstype=squashfs 
secboot=1 
stderr=serial0 
stdin=serial0 
stdout=serial0 
write_defaults=1

Bootlog i make it now :-)



Edited 1 time(s). Last edit at 11/19/2025 11:21AM by Quantummaster.

Quantummaster,

It won't work without other changes, not just flashing the image.

1. In the log, the bootargs showed there are other differences between A and B. And the differences are: mtdparts layout (NAND vs SPI device), and the UBI device. Probably UBIFS layout is the same (only image volume).

2. The bootargs is hard coded in u-boot before it loads the kernel.

3. The u-boot (loader) can not be transfered from A to B since it's NAND flash in A and SPI NAND flash in B.

-bodhi
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Edited 2 time(s). Last edit at 11/19/2025 04:42PM by bodhi.

You could try dumping the image partition and mount it in Linux. See if there are things that could prevent u-boot from loading the image.

I'm guessing once you see the image layout, you could see how things need to be moved around as router B expects.

-bodhi
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Forum Wiki
bodhi's corner (buy bodhi a beer)



Edited 1 time(s). Last edit at 11/19/2025 04:48PM by bodhi.