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Subject: Re: Improved crt0-pp.S for PortalPlayer targets (iPod, H10 and Sansa)

Re: Improved crt0-pp.S for PortalPlayer targets (iPod, H10 and Sansa)

From: Barry Wardell <barry.wardell_at_gmail.com>
Date: Sat, 9 Dec 2006 19:58:34 +0000

I tested this on an iPod color without success so far. For some
reason, the new bootloader crashes before even showing anything on the
LCD. I've also had a similar report with an iPod nano.

On 12/5/06, Barry Wardell <barry.wardell_at_gmail.com> wrote:
> Hi,
> I've been working with Daniel Ankers on getting a dual bootloader
> working on the Sansa (and also on the H10). In doing so, it was
> necessary to make some changes to crt0-pp.S (patch attached). The
> purpose of the changes was to:
>
> * Make sure only the CPU clears the BSS (not the COP)
> * Give the CPU and COP separate stacks
> * Make the bootloader run from IRAM so it's not overwriting the SDRAM
> * Flushing the cache as appropriate (before waking up the COP)
> * Remove the unused DEBUG and STUB code (which was only ever used for
> the iFP port afaik)
>
> I'm told that the current crt0-pp.S in CVS is very very multiprocessor
> unsafe because of the reasons fixed in this patch, so it's quite
> possible that some random behaviour in iPods may also be fixed by
> this, particularly things related to the COP.
>
> I've tested on my own H10 and Sansa with great results - dual booting
> works now where it didn't before. However, I don't have an iPod to
> test on so I'm asking for people to help with testing it. Both
> bootloader and normal builds need testing and it would also be good to
> know if a new bootloader works with an old build of Rockbox and vice
> versa (this wasn't the case with my H10 but was with the Sansa). It
> needs to be tested to see if Rockbox loads OK and if playback, etc.
> still works as it did previously.
>
> Thanks,
> Barry
>
>
>
Received on 2006-12-09


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