Booting and debugging Linux on IXDP425

Hi there, I am trying to get Linux to boot on an IXDP425 board (Intel IXP425 development board) with no luck. I have Redboot running OK, but when I load zImage and ask Redboot to run it with "exec" it locks up and nothing happens (no "uncompressing..." prompt or anything). I'm using the Snapgear Linux distribution. I have tried a precompiled Linux image from the Gatewaymaker project

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and get the same result. What I'd like to do is step through the Linux startup code with my debugger, but I have a few questions about doing this.

I'm using a home made "Wiggler" parallel port JTAG adapter. This seems to work fine (although I have to run OcdLibRemote on a Windows PC) with GDB for small simple programs (I used it to load my program that programmed Redboot into the Flash), but I cannot connect to the target and make it run Redboot (either out of ROM or RAM). Surely I should be able to connect to the target with GDB and the Wiggler and just tell it to continue and have it run Redboot? If I try to run Redboot from Flash with GDB and the Wiggler I get a "Target Bus Error" from OcdLibRemote as soon as I single step on the first instruction at 0x0.

The other thing that confuses me is how to make sure that my Linux image is located correctly. The latest version of Redboot for the IXDP425 seems to want to run Linux from 0x6000000. As far as I can make out I should be able to edit vmlinux.lds to make sure that it is built to load there, but that doesn't make any difference and there are several vmlinux.lds files (which one is used, arch/arm/vmlinux.lds or arch/arm/boot/compressed/vmlinux.lds ?).

Any advice would be greatly appreciated.

- Charles

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Charles Oram
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