Status of gprs? (and a bit of a hello world)

[Simon]

Ok, excellent, I'll give a few things a try!
Thanks!

On Tue, May 12, 2009 at 4:34 AM, Tobias Diedrich <ranma at tdiedrich.de> wrote:
> Simon wrote:
>> documentation on how to achieve this on forums.  There seems to be all
>> the tools already available for setting up a proper bootloader.
>> But one thing i wasnt able to find is this:
>> There is currently windows mobile on it and as much as i dislike it,
>> it does work.
>> Would it be possible to change the bootloader to do some kind of dual
>> booting?  Where the WM would remain on phone's memory and my linux
>> install would be on the external 2gb microSD...  is this possible or
>> would the process wipe WM or make it inacessible? (I guess my question
>> is, does WindowMobile require a special bootloader?)
>
> If you haven't found information about dual booting on the forums,
> then it's likely no one has written a bootloader that can do it yet.
>
> It could be as 'easy' as modifying the windows bootloader to check
> if some button is pressed or not when you turn it on and then branch
> to the bolted on linux bootloader (which would then have to load
> the kernel from microSD) or continue booting windows.
>
> But you'd have to be knowledgable about the target platform,
> dissambling and stuff like that to create such a modified
> bootloader.
>
> *google*
> Actually, it looks like there already is a loadlin-like Linux loader
> for Windows CE called Haret.
> http://grigio.org/howto_openmoko_htc_magician_s100_dual_boot_wince
> http://www.handhelds.org/moin/moin.cgi/HaRET
> Maybe this works for your phone?
>
> This one likely uses a bug in Windows CE (or maybe all CE apps run
> with full rights?) to break into kernel mode and start the Linux
> kernel.  With that one no bootloader modifications are needed,
> however you always have to boot WinCE first and then start Linux
> with this application.
>
>> Hmmm, well, i wanted to work in assembler these days! haha, i'd still
>> prefer not having to reverse engineer anything though, i'm just
>> curious, what would i reverse engineer?  I believe the CPU will
>> contain a real ROM that was burnt from the begining to tell the cpu
>> that it has to read the EEPROM and execute it...  so i guess i would
>> have to study that 'thing' and the current bootloader?
>
> If there was no alternative bootloader already, then yes.
>
>> > However, once you have managed to get Linux up and running,
>> > porting OpenMoko to your device should be the easiest part. ;)
>>
>> Ah, relief!  So you mean, as soon as the kernel starts and works until
>> it starts init, at that point all i need is to setup the root
>> filesystem with openmoko as the distribution and load the kernel with
>> root=... and since i'm considering using the uSD i might have to add a
>> delay=...  I guess OM also comes with some kind of initrd (i actually
>> prefer to avoid those and have the necessary builtin to the kernel if
>> possible).
>
> Basically yes.  You may have to compile stuff yourself, if the target cpu
> is not compatible to the existing binaries (different arch or
> missing features).
> Also, you'll surely have to tweak some things, like code concerning
> battery management/charging and the power managemant unit, stuff
> like how to turn on/off different parts of the phone, how/where the
> buttons are hooked up, what kind of X server to use for your
> hardware and so on.
>
> --
> Tobias                                          PGP: http://9ac7e0bc.uguu.de
>