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Re: MCM2+8 with external Flash
On Wed, Oct 22, 2003 at 07:52:58PM +0200, Bernhard Roessmann wrote:
> Hi again,
> I am using a MCM2+8 with 8MByte external flash chip (AMD AM29LV640MT).
> My ptablespec looks like this.
> # name size rw-options type image-file
> rescue 0x010000 ro rescue rescue.img
> flash1 0x1F0000 ro kernel flash1.img
> flash2 0x200000 rw jffs flash2.img
> As you can see, the whole internal flash (2MB) is used for rescue and
> flash1, the external flash as flash2 (only 2MB first).
> Everything works fine now.
> If I increase flash2 now up to 0x600000 (6MB), the MCM boots after
> flashitall and works normally. But it doesn't boot anymore with "normal
> boot" option (serial kernel output shows nothing!).
> If I increase flash2 beyond 6MB, e.g. 0x800000 (8MB, which ist the
> external flash size), MCM NEVER boots, neither after the reboot after
> flashitall nor with normal boot mode.
> Whats wrong?
I'm not sure exactly how RAM is used by the boot loader, but I know that
it loads the entire flashimage to RAM before writing it to flash. So you
may need more than 8MB RAM to be able to flash a 6MB image. Maybe
someone else can explain the bootloader internals?
I suggest that you exclude the jffs-partition from your fimage and
initialize the jffs partition on first-time boot using eraseflash and dd
to write an unpadded factorydefault-image /usr/etc/defaultfiles/jimage
to the character device.