Am 10.06.2010 um 20:44 schrieb Ruben Viets:
Hi Nikolaus,
How did you damage it ? That is not easy.
I can't tell exactly. I did experiment with mounting the mtdblk4 and 5
and it did choose and find a yaffs2. Then I got some write errors as
described in the other mail.
After "shutdown -h now" the machine did not switch off completel so I
pressed the power button for 5 seconds. Then, I copied a new version
of my kernel to the SD card but it did not boot any more. Even the old
kernel did boot. And, there is no apparent reaction on the U-Boot
modifier keys. Not even after removing and reinstalling power supply
and battery.
- You could try the reset button at bottom. If you are lucky your
jz4730 was only stuck and will be able to boot again.
A, good idea that I can try. Hm. Has no differnent effect as pressing
the power button for 5 seconds.
Some other info and hints:
- Could be the LPC915F MCU is companion for boot ?
http://projects.kwaak.net/twiki/bin/view/Epc700/HardwareLayout
According to the data sheet this is the power controller. The only
interface to the CPU allears to be I2C
- Check some debug info on simular debug boards
ftp://ftp.ingenic.cn/4hw/01_DEV_board/DB4730_Libra/DB4730_Libra-SW-EN.pdf
Interesting information. I think the Libra is a board having NOR (ROM)
and NAND flash, while the Mipsbook only has NAND.
The document shows that booting from NAND is using a special first-
stage boot loader. This should be the first 4k block in the U-Boot
partition. So I think I may have to restore both, this NAND loader and
U-Boot...
- Flashing yourself via JTAG could be difficult, because you need to
have some flasher tool and the original uboot.
Check ingenic manual.
tp://ftp.ingenic.cn/3sw/00tools/jdi/manual/JDI-Manual_EN_1.4.pdf
Well, I have an Openmoko debug board...
But....
* no idea if it is compatible (starting from logic levels on JTAG port)
* how to acces the JTAG port (cable? Pogo pins?)
* how to access registers or pins of the CPU
* how to manipulate these to correctly address the NAND flash
So I think it *can* be done. But is another major project :((
And I had not planned to learn JTAG and develop a JTAG tool...
Any Volunteers around?
- Ask on dutch forum for http://trendtac.hyves.nl/
- Login to irc.freenode.net #mipsbook ask person there.
Hopefully you'll fix it.
If I do, we all have gained a lot...
For the meantime I have to take another machine to convert into a
brick :)
BR,
Nikolaus
Grt Ruben.
> From: h...@computer.org
> To: mipsbook-devel@linuxtogo.org
> Date: Thu, 10 Jun 2010 19:36:21 +0200
> Subject: [Mipsbook-devel] how to recover U-Boot...
>
> Although I have not verified by connecting a serial console, it
looks
> as if I have damaged the NAND partition with U-Boot while
> experimenting with yaffs2 drivers :(
>
> Now, I can't boot the machine any more. it does no longer respond to
> different Fn keys as described at
http://projects.kwaak.net/twiki/bin/view/Epc700/UbootStuff
> ).
>
> Looking into the datasheets gave initial hope - but only the JZ4740
> has an internal Boot ROM that can boot from USB (by exposing the
> device as a client to a host). The JZ4730 can only boot from NAND
or a
> connected ROM. So if bootsel is hardwired (I assume it is) and there
> is no external ROM (we have no info about such a thing), only JTAG
> remains.
>
> Any ideas? Hints? Experiences? Experienced guys to contact?
>
> BR,
> Nikolaus
>
>
>
>
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