No subject

[Mike Bushroe]

*Author: *Douglas Jerome <douglas at ttylinux.org>
> *Date: *2014-05-13 20:48 -700
> *To: *Main PLUG discussion list <plug-discuss at lists.phxlinux.org>
> *Subject: *Re: Anyone with experience in Cross-Compiling, especially to
> an embedded powerPC?
>
> If it that easy, then maybe migrate through the files in
> something like 1K chunks with dd, writing the next 1K chunk
> from the file in flash to a 1K file on RAM Disk then back.
>
> I think this is just for the few files in /boot, to refresh
> the kernel, yes? The kernel is running in RAM, so you can
> write to it the kernel binary file in /boot while running.
>
>
Actually, the kernel is the one thing I was not going to do in this go
round. Since we have the image file and instructions for re-imaging the NOR
flash with the kernel image, if we get permission to do that, I would use
that approach instead. And if they had fielded either of the last two
firmware upgrades that require the new kernel, even that would not be a
question as the NOR would have been recently refreshed already. It is more
the files in /boot, /bin, and /sbin that I am worried about getting
refreshed. And some of the files in /bin and /sbin might be open and in use
while trying to do the update, which is what has me going around the long
way around.

I would be afraid of using dd because of the bad blocks. Although yaffs
puts all the directory and file data for each page in the out of band bytes
for each page, so that you could copy each page somewhere else and it would
still work, that still seems a bit risky. If we use the file functions
through yaffs, it will not only work around any bad blocks, but also
increment the 2 bit page counter so that it can tell which page is current
if power drops suddenly while the old and new versions are both still
resident. And it will also mark the old pages as deleted and erase blocks
where it can, so that should cover more ground than using dd directly.
However, I have used dd to read the binary image of the flash, including
the OOBs. But I have not yet decoded them enough to write a script to
duplicate the processes in yaffs.

Mike
-- 
"Creativity is intelligence having fun." — Albert Einstein
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