[syslinux] PXELINUX: how to debug initrd corruption?

[Andy Walls]

Hi All,

I have a system, that, ~80% of the time, fails to properly boot using
pxelinux.0 as provided by RHEL 5.5 (syslinux 3.11, I think).  The
gripe, before the console messages stop, is a message that comes from
the linux kernel complaining the compressed ram drive image is bad:
"invalid compressed format (err=[small number])".

I have two questions:

1. How should I go about debugging the problem to find the root cause of
the initrd image corruption?

I've examined the TFTP transfers with Wireshark; they appear OK.
I have not tried a more modern pxelinux.0 yet.


2. Can anyone provide a description or simple diagram of what regions of
system memory PXELINUX uses?

>From the linker file, I know that .earlybss starts at 0x800 (or 0x1000),
and a number of sections directly follow it.
I also realize some allocated regions are system specific, depending on
what the BIOS returns in its E820 map.
I am, not surprisingly, interested in the regions where PXELINUX stores
the kernel and initramdisk images after TFTP-ing them over.

Thanks.

Regards,
Andy