[maemo-developers] [maemo-developers] Getting scratchbox CPU transparency working on the n770

[From: Carl Worth]

A while back I managed to get scratchbox CPU transparency working on a
Nokia 770. It's extremely cool voodoo, and very handy.

I just ran through the process again tonight, and took careful notes
on what I had to do. Some parts of it were a bit painful, (and some
even got a bit worse than the last time I tried). I've attached my
notes to myself below, (maybe there's some good wiki fodder in here,
but I don't know---a lot of it is redundant with other more thorough
pages scattered about the wiki already).

The question I have is whether some of this couldn't be made much
simpler in the "standard" latest software editions. In the
instructions below, I start with an older "Internet Edition 2006"
install (to get a kernel that works) and then also drop back to a
"developer" root filesystem to get the check boxes for UsbNet and CPU
transparency.

This is really handy stuff, but it's a shame to give up all the fancy
new software on this gadget in order to get at it. How hard would it
be to be able to add this support to a recent install? For example,
could that be made just a matter of a couple of extra packages?

As for the kernel issues, with the 2.2006.39-14 release I wasn't able
to get "modprobe nfs" to work. It complained about something that made
me think depmod needed to be run, but then depmod didn't work at
all. I didn't explore further at that point but instead just dropped
back to 1.2006.26-8 since I knew I had gotten this all to work at some
point in the past.

Anyway, are other people doing things like this? If so, how are you
going about it? Are you making custom images, etc?

-Carl

First, let's get that n770 into a known state. This requires
downloading a flasher binary and a software image. The flasher binary
(for several platforms) is available here:

	http://www.maemo.org/downloads/d3.php
	(With annoying click-through license)

I used flasher-2.0, and that may be a requirement.

Next, you'll need an image to flash. Get the following file:

	SU-18_2006SE_1.2006.26-8_PR_F5_MR0_ARM.bin
from:
	http://www.maemo.org/downloads/nokia_770
	(Again, with annoying click-through)

Don't be tempted by the newer 2.2006.39-14 release---the kernel it
comes with doesn't come with the necessary kernel modules.

So, now flash that image by following these steps:

1. Power off the n770 (hold down the power button on top for a few
   seconds)

2. Connect it to your host with the provided USB cable

3. Run the following on your host using the files downloaded above:

	sudo ./flasher-2.0 -f -R -F SU-18_2006SE_1.2006.26-8_PR_F5_MR0_ARM.bin

   NOTE: At this point, the command will appear to hang with what
   looks like an error message, ("Suitable USB device not found,
   waiting"). This is normal and expected, just keep going.

4. Press the power button on the n770 for a second or so.

   The flashing should now proceed with progress indicators on both
   sides, and the n770 should reboot when finished. You can now play
   around with the applications installed for a bit, (since the next
   step will wipe them out).

The applications have a lot of polish, but this image doesn't include
a couple of things we really want, (USB networking, and scratchbox CPU
transparency), so we're going to install a "Developer Image" that
misses a lot of applications and polish, but lets us get some work
done.

So, now download the following:

	Maemo_Dev_Platform_v2.1_armel-rootfs.jffs2
from:
	http://www.maemo.org/downloads/d1.php
	(A third, annoying click-through(!))

Then repeat the flashing process, but the details of the flash command
are different since this is just a root filesystem, not a "fiasco"
image with kernel, initfs, rootfs, etc. So the steps once again are:

1. Power off n770

2. Connect it

3. Run the following command:

	sudo ./flasher-2.0 -f -R -r Maemo_Dev_Platform_v2.1_armel-rootfs.jffs2

4. Power on the n770 and watch the flashing proceed

If you had played with the previous software install at all, then
you'll probably notice a few differences. Such as a big black SDK when
booting instead of the two hands, a drab gray theme instead of the
flashy orange stuff, and many fewer applications installed.

But the important difference is a little icon on the top of a wrench
in front of a blue USB symbol. Click on that and make sure that UsbNet
is selected rather than MMC and also that the "Enable
cpu-transparency" option is selected.

From here on out the n770 should be all set. What still needs to be
done is to setup the following on the host machine:

1. USB networking scripts

2. Scratchbox installation

3. NFS server exports

4. Scratchbox configuration

And maybe a couple of other things I've forgotten, (though there are
already a lot of details in just the 4 things above that I still need
to remind myself.)
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