[U-Boot] U-Boot ram disk

[U-Boot] U-Boot ram disk

[Nuno Cardoso]

hi,

the big problem is that I have an embedded system where I don't know the
login password to login. I forgot the password, and try and try... but I
can't remember. The system had some important information, so I want to
restore the system.

The steps that I want to follow are:
1) save the target rootfs to my machine;
2) mount the filesystem on my machine;
3) change the rot password;
4) finally, store the new file system on the taget machine (embedded
system).

To do the first step, I need to save the rootfs image on my machine to mount
it. So, I need to stop the u-boot initialization, before the login step, to
save the rootfs. But, U-Boot doesn't have any kind of command to do that.

Can I load the rootfs from NAND Flash to ramdisk (nand read xxxx rootfs
size) and print the memory at address xxxx from memory to display (md xxxxx)
and save the GTKTerm display to a local file and do some kind of process to
remove the wrong caracters??? Maybe with this I can do this??? What is yout
opinion????

Thanks a lot,
Nuno Cardoso.

[U-Boot] U-Boot ram disk

[Scott Wood]

On 05/03/2010 05:33 PM, Nuno Cardoso wrote:
> hi,
>
> the big problem is that I have an embedded system where I don't know the
> login password to login. I forgot the password, and try and try... but I
> can't remember. The system had some important information, so I want to
> restore the system.
>
> The steps that I want to follow are:
> 1) save the target rootfs to my machine;
> 2) mount the filesystem on my machine;
> 3) change the rot password;
> 4) finally, store the new file system on the taget machine (embedded
> system).

Have you tried adding "init=/bin/sh" to the bootargs variable?

> Can I load the rootfs from NAND Flash to ramdisk (nand read xxxx rootfs
> size) and print the memory at address xxxx from memory to display (md xxxxx)
> and save the GTKTerm display to a local file and do some kind of process to
> remove the wrong caracters??? Maybe with this I can do this??? What is yout
> opinion????

I suppose you could do this (using something like xxd to undo the hex 
dump), but that would be a lot to copy and paste.

The only other option I can see from a quick look is the "saves" command 
to upload data to the host in S-record format.

-Scott

[U-Boot] U-Boot ram disk

[Nuno Cardoso]

hi list,

Is it possible copy a file from ramdisk address on target machine (U-Boot
command line) to host machine. I want to save the linux kernel image saved
inside the Nand Flash, to a directory inside my machine. Is it possible???

Thanks,
Nuno Cardoso.

[U-Boot] U-Boot ram disk

[Wolfgang Denk]

Dear Nuno Cardoso,

In message <k2i3cf2debb1005030943j5f36981k5ad16afca164f387@mail.gmail.com> you wrote:
>
> Is it possible copy a file from ramdisk address on target machine (U-Boot
> command line) to host machine. I want to save the linux kernel image saved
> inside the Nand Flash, to a directory inside my machine. Is it possible???

Your request makes little sense to me.

If the kernel image in stored in NAND flash, then there is no "ramdisk
address" for it, first because the kernel is not a ramdisk, and second
because NAND flash is a storage device which has things like block
numbers or offsets but no such thing as addresses.

"Save ... to a directory" does not work in U-Boot either, as all file
system support is read-only.

Best regards,

Wolfgang Denk

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