Hey Jon - If you do figure it out, please add it to the wiki. I am
waiting for a JTAG myself, didn't notice the Guruplug did not have the
serial built in.
Cheers,
-Joe
On Tue, 11 May 2010, Jon Hermansen wrote:
Itamar,
I have read over many guides, including the Fedora wiki, Ubuntu
ARM-specific wiki pages,
plugcomputer.org, and a few other places but yet
have not found what I've been looking for. All the pages I've read
specifically refer to accessing U-Boot over serial (using the $40 box from
Global Scale, or I can DIY) from another PC, and I can't do this at the
moment. Specifically, I think the problem boils down to knowing specific
offsets to data on the NAND on my GuruPlug board.
There are existing tools that will supposedly do what I want -- flash
onboard NAND:
1. mtd-utils:
http://www.linux-mtd.infradead.org/
2. sheeva-uboot-tools:
http://code.google.com/p/sheeva-uboot-tools/
I assume that the latter tool relies on the former. Now, fw_printenv (part
of mtd-utils) always throws "bad CRC" at me because I haven't figured out
the correct offsets/sizes yet. I've done a nanddump on the partitions of the
MTD that have the interesting bits on them, namely, the u-boot loader and
the kernel. There is a third partition, that holds the rootfs:
[root@guru ~]# cat /proc/mtd
dev: size erasesize name
mtd0: 00100000 00020000 "u-boot"
mtd1: 00400000 00020000 "uImage"
mtd2: 1fb00000 00020000 "root"
I looked at the uImage bit in a hex editor, and found nothing interesting or
configurable, just kernel junk. In the "u-boot" partition, I have found bits
that look like configuration information, but I _do not_ want to modify the
default u-boot options, in fact, I'd rather leave them in case I get a JTAG
cable later or do something to bork my OS. I also can't discern where in
this file lie the custom settings vs. the default settings, so I won't
change any bits here yet...
I have considered another alternative, that is, only flashing over the
uImage and rootfs MTD partitions. This would be fine, assuming that the
shipped version of U-Boot does not limit functionality on my system... and I
think this would allow me to install Fedora 12.
An additional alternative would be to fake passed parameters to the kernel,
i.e. hack the kernel source to default to "root=/dev/sda" and thus
overriding my current /proc/cmdline:
[root@guru ~]# cat /proc/cmdline
console=ttyS0,115200 ubi.mtd=2 root=ubi0:rootfs rootfstype=ubifs
If anyone has any more information, please advise. I am considering writing
to Global Scale / the kernel developers over at Marvell to see if they can
drop me any hints...
On Sun, May 9, 2010 at 9:30 PM, Itamar Reis Peixoto
<itamar(a)ispbrasil.com.br> wrote:
On Sun, May 9, 2010 at 3:46 AM, Jon Hermansen
<jon.hermansen(a)gmail.com> wrote:
> Hello all,
> I just got a brand new GuruPlug a few days ago and I was hoping to
install
> Fedora ARM on it as soon as possible. Well, the only problem is, I
neglected
> to get the JTAG breakout box / cables required to get the U-Boot
prompt and
> thus, as far as I can tell, can't do much about loading a new U-Boot
version
> (hopefully to boot from microSD), putting a new U-Boot config, Linux
kernel
> and accompanying rootfs on the NAND/external MicroSD card. I can see
the
> /dev/mtd* devices from Debian 5.0.3, kernel 2.6.32-00007-g56678ec,
but I
> have yet to write to them from my live system as I want to be
absolutely
> sure about what I'm doing on this front.
>
> I'd also like to know if I can use the internal NAND/external
MicroSD card
> as one big device, as opposed to two seperate devices. I realize the
NAND is
> not addressed as a block device, but if they both can contain
filesystems,
> does that mean that I can use UnionFS (or something similiar) to
bridge two
> seperate filesystems and divide the space taken up by data between
the two
> storage devices?
>
> If anyone could provide any more information on what I'm attempting
to do
> (flash NAND, reinstall OS) without a JTAG cable, either on a
SheevaPlug or a
> GuruPlug (from what I've read, they are nearly the same), it would
be
> greatly appreciated.
>
> Thanks to all of you guys for working out the kinks in Fedora ARM,
and I'm
> looking forward to using my favorite distro on the smallest PC I've
ever
> had...
>
> Jon Hermansen
>
start here ->
https://fedoraproject.org/wiki/Architectures/ARM
--
------------
Itamar Reis Peixoto