virt-install / xen domU 'out of memory' issue

I had today to deploy two CentOS 5.3 xen dom0 on two blades and then some domU's guests. Everything was fine except that when i used our traditionnal deploydomU script (which uses virt-install) it directly complained about memory issue. The exact message was " 'Out of memory', "xc_dom_boot_mem_init: can't allocate low memory for domain\n" " . Strange as I was sure that the dom0 had plenty of memory and the new guest was defined to use only 768Mb .. so what was the issue ? In fact, nothing related to memory : Our new machines get deployed through a pxe boot menu (with syslinux/pxelinux.0 and pxelinux.cfg) in the Labs zone, but a typo was inserted in that menu so that newer CentOS 5.3 x86_64 machines were in fact ... using i386 repo !  ;-)

It took me 5 minutes to consult the great oracle (aka google) , find the same issue and look at both new nodes to confirm with `uname -a` that I tried to deploy a x86_64 domU on a i386 dom0 ...

Hehehe, strange that the message is related to memory and not arch .. but several minutes later (and a coffee cup, machines being redeployed correctly *after* the pxelinux.cfg file was modified) everything was back to normal and x86_64 domU's running fine ... hope that it can help other people having the same 'typo' :-p