REC: Any configurable bootloader on Zaurus SL-5600? Options

[SiliconBear]

All,

I've got my SL-5600 for several months. And interested in booting it into OS other than Sharp's Linux.
I'm wondering whether the default bootloader(Angel?) could help me to boot into something like BSD or eCos.
It seems that people could install RedBoot in iPaq(running winCE), then boot iPaq into Linux. Is that true? Maybe we could do the same thing on Zaurus.
Oh, one more thing, Unlike WinCE, the Sharp Linux is open sourced. I don't understand why Sharp wants to prevent us booting into a non-standard OS. The only reason I can come up is a larger expense on tech. support.

Thanks,
Bear.

[tumnus]

There's no configurable bootloader as far as I am aware. The only way to boot into a completely separate OS is through building your own ROM.

The reason why you can't do this with WinCE/Pocket PC/etc is because it's closed source yet there are modifications that you have to make for the hardware. You can only do this by becoming a WinCE licencee, which is very expensive.

[Mickeyl]

I recommend porting LAB (Linux As Bootloader), the next-generation handhelds.org bootloader - to the Zaurus family of devices.

[SiliconBear]

Thanks for all the replys...

I couldn't find the current source of LAB. Probably it's only available via cvs or bitkeeper?

After googling whole day. I found that what I was looking for is something like "kexec" system call. I'll look into the possibility of porting it to arm/xscale...

Thanks again!

Bear.

[Mickeyl]

LAB is contained in the handhelds.org kernel cvs.

[SiliconBear]

I have completed most of the machine dependent code in order to port kexec to Xscale. Now, I could load a zImage file in terminal, then turn off MMU, and bracnh to 0xa0008000. So far, the new kernel is stuck at:

init started: BusyBox V0.60.4(2002.10.26-08:50+0000) multi-call binary
Bad inittab entry: id:5:initdefault:
No more tasks for init -- sleeping forever.

I guess I need to read more about busybox and how does zaurus use busybox in boot-up procedure....
Any clue/hint? :-)

Thanks again!

Ref: http://developer.osdl.org/rddunlap/kexec/

Thanks for all the replys...

I couldn't find the current source of LAB. Probably it's only available via cvs or bitkeeper?

After googling whole day. I found that  what I was looking for is something like "kexec" system call. I'll look into the possibility of porting it to arm/xscale...

Thanks again!

Bear.

[SiliconBear]

It turns out that Sharp's bootloader always feeds the old style params struct instead of tag list. After hardcoding exactly the same params in the kexec utility, now my SL-5600 can boot.
I put the patch at http://mysite.verizon.net/vze6y4s8/id1.html, although it proably doesn't make much sense to most of users...

Take care!

[Mickeyl]

Could you tell us a bit more details? I really don't see the benefit of using kexec on non-x86 machines. Are you no longer working on an alternative to the angel bootloader?

[SiliconBear]

Hmm, I'm not interested in "fast" boot as well.
I want to bootup other OSes on Zaurus, could be NetBSD or eCos. With kexec, I could boot into Sharp Linux first, then load and boot into, for example, NetBSD. Therefore, later on, if we can find a way to configure Angel or maybe burn a real bootloader into flash. We will have a ready-to-use NetBSD.
I haven't really spent much time on replacing Angel. The major reason is that without JTAG, I guess I will turn my Zaurus into brick very quickly. Then I won't have anything to play with. Do you know anyway to restore Angel back to Zaurus?
I agree that we will need to burn a bootloader into flash to make it useful. But, after knowing that Sharp doesn't want us to know how to use the JTAG. I'm less interested in this work now.

Could you tell us a bit more details? I really don't see the benefit of using kexec on non-x86 machines. Are you no longer working on an alternative to the angel bootloader?