>Hi all,
>In cheap home routers it happens that bootloaders perform some checks to
>allow only vendor-approved firmware releases.
>Bootloaders are tiny -usually 64 bytes- and often contain meaningful
ITYM 64 KiB.
>strings about check errors, so it shouldn't be hard to decompile and
>change the conditional jumps and avoid checks.
If the bootloader is part of the controller's flash, it might be protected
and cannot be read out.
--
Dipl.-Inform(FH) Peter Heitzer, peter.heitzer@rz.uni-regensburg.de
HTML mails will be forwarded to /dev/null.
Reply by David Brown●March 10, 20152015-03-10
On 10/03/15 18:25, Gianguido wrote:
> Hi all,
> In cheap home routers it happens that bootloaders perform some checks to
> allow only vendor-approved firmware releases.
> Bootloaders are tiny -usually 64 bytes- and often contain meaningful
> strings about check errors, so it shouldn't be hard to decompile and
> change the conditional jumps and avoid checks.
>
> I have some very basic knowledge about decompiling/disassembling for x86
> and would like to try and disassemble these bootloaders.
> Architectures is usually MIPS/MIPSEL.
>
> would you have any suggestions about where to start? ie. if you know
> some tools and or examples out there?
>
> thanks
> G.
Most cheap home routers can be used with alternative firmware by simply
"updating" them with properly built images. The biggest project
covering this sort of thing is www.openwrt.org - they also have
information about bootloader configurations for a large number of routers.
Reply by Gianguido●March 10, 20152015-03-10
Hi all,
In cheap home routers it happens that bootloaders perform some checks to
allow only vendor-approved firmware releases.
Bootloaders are tiny -usually 64 bytes- and often contain meaningful
strings about check errors, so it shouldn't be hard to decompile and
change the conditional jumps and avoid checks.
I have some very basic knowledge about decompiling/disassembling for x86
and would like to try and disassemble these bootloaders.
Architectures is usually MIPS/MIPSEL.
would you have any suggestions about where to start? ie. if you know
some tools and or examples out there?
thanks
G.