[U-Boot] stopping u-boot from booting an old image in RAM.

[David Collier]

In article
<610D18D1F0BB204D8AB39BB1C42187E8041E739E at LONMLVEM09.e2k.ad.ge.com>,
Nick.Thompson at gefanuc.com (Thompson, Nick (GE EntSol, Intelligent
Platforms)) wrote:

> *From:* "Thompson, Nick (GE EntSol, Intelligent Platforms)" 
> <Nick.Thompson at gefanuc.com>
> *To:* <from_denx_uboot at dexdyne.com>, <u-boot at lists.denx.de>
> *Date:* Wed, 21 Oct 2009 16:39:18 +0100
> 
> > -----Original Message-----
> > From: u-boot-bounces at lists.denx.de 
> > [mailto:u-boot-bounces at lists.denx.de] On Behalf Of David Collier
> > Sent: 21 October 2009 16:08
> > To: u-boot at lists.denx.de
> > Subject: [U-Boot] stopping u-boot from booting an old image in 
> > RAM.
> > 
> > If I boot this unit, then remove the SD card it booted from and 
> > reset it,
> > it happily boots some Linux image which is lying around in memory.
> > 
> > It even does it after a short power-off power-on sequence.
> > 
> > I think that's horrible behaviour.
> > 
> > I was told I could use && instead of ; between the commands in the
> > bootcmd string to stop this, but that barfed, and then I was told 
> > that
> > maybe && only existed if "scripting is enabled"
> > 
> > Could anyone please talk me through the steps of either
> > 
> > 1. doing what it takes to enable this && feature, so that if it 
> > fails to
> > find the card, it doesn't go on and try to boot.
> > 
> > or
> > 
> > 2. something else that will do it, such as so effectively 
> > buggering up an
> > image that has been booted from that it will never be re-used
> > 
> >  :-)
> > 
> > TVM
> > 
> > David Collier
> 
> Probably a simple mw (memory write) to the entry point of linux, 
> before
> You attempt to reload the image, would do the trick?
> 
> Usage:
> mw [.b, .w, .l] address value [count]
> 
> Nick.
 
so something like

#define CONFIG_BOOTCOMMAND						\
	"mmcinit ; mw 0x10400000 55 ; ext2load mmc 0:1 0x10400000  /boot/uImage ;
bootm 0x10400000"

????

That looks simple enough        
        
David Collier

www.dexdyne.com