[Arm-netbook] microSD breakout board, suitable for debugging using tablets.

Alejandro Martínez zen at itram.es
Wed Feb 8 20:02:44 GMT 2012

>> You need to modify script.bin for serial output as well. Default for
>> those pins are SD.

I know, see the page I linked to :) I also made a tool that will also
decompile the script.bin back into the .fex plain-text format so it
can be easily modified and then rebuilt, see

> > Anyway, after some (failed) attempts of making the tablet boot using the SD
> > card as boot (so no Chroot needed), and trying it to show a framebuffer
> > console, became stuck with no output at all from the kernel.
> can you document this?

It is easy, the Gingerbread ROMS don't use u-boot but a custom
bootloader which has the route to the kernel and the parameters passed
to it on .ini and plain-text files.

I modified the kernel parameters for the recovery kernel (on a file
called params_r) to make it use /dev/block/mmcblk0p2 as root instead
of /dev/block/nandX (can't remember the original letter). But when I
do so, nothing appears on the screen. I probably need to insert some
kernel modules (lcd.ko), but as the only possible output (the display)
is off, I have no way to know what is going on.

Compiling my own kernel was easy, though - found a tarball with
everything and the default configuration worked on the tablet. Anyway,
the kernel seems to have device-specific stuff on it (regarding
screen, etc) because other tablet kernel and modules don't work
properly on mine...

> considering you can solder (I can not :-/) you may also try
> http://www.tuxbrain.com/en/oscommerce/products/1898 ... they are here
> in Spain so shipping will be much faster than sparkfun :)

Oh, I hadn't seen that one.. anyway the contacts seem too small for my
limited soldering skills :( The Sparkfun one is easier as I can just
solder some headers and forget about it.
And I can also reuse it for talking to a MicroSD with an Arduino.. or
even use some unused pins on the SD to get serial output with a SD
Anyway, I ordered it last week so it should come here this week or the next one.

People on Slatedroid are already working on decrypting and
reencrypting the boot images/bootloaders for the tablets:

so I think EOMA software development efforts will be quite useful for
the tablet-hacking community :)

Alejandro Martínez

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