I'm going round in circles and banging my head against a brick wall so 
it's time to call in the experts :)
To set the scene I'm running Fedora 12 with 2.6.31.5-127
I've bought a shiny new samsung laptop. Problem is that it appears the 
hardware is *too* new. Everything seems to be up and running apart from 
the onboard NIC (Marvell Technology Group Ltd. Device 4318), and 
wireless card (Realtek Semiconductor Co., Ltd. Device 8192).
I'm just focussing on the ethernet at the moment, the wireless I'll dig 
into when I can actually get some packets flowing.
The device is supported under kernel 2.6.32.8, so I'm trying to get this 
onto the networkless laptop.
I've downloaded the source from kernel.org on my other laptop, run 'make 
menuconfig' and set what I believe to be the right (and safe) options.
Then 'make bzImage', 'make modules' and 'make rpm'. This all ran without 
failure and I moved my fresh rpm over to the new laptop.
I ran 'rpm -ivh kernel.blah' and it installed seemingly successfully. 
'mkinitrd /boot/initrd-.blah blah' to create the ramdisk image.
I was however expecting the rpm install to update my menu.lst but it 
didn't. I believe I've put everything in the right places, using the 
default entry as a basis:
title Fedora (2.6.31.5-127.fc12.i686)
     root (hd0,4)
     kernel /vmlinuz-2.6.31.5-127.fc12.i686 ro 
root=/dev/mapper/luks-2ddd7768-d55b-4b7c-857d-d346505c3bed noiswmd 
LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=uk 
rhgb quiet
     initrd /initramfs-2.6.31.5-127.fc12.i686.img
title Fedora (2.6.32.8.fc12.i686)
     root (hd0,4)
     kernel /vmlinuz-2.6.32.8 ro 
root=/dev/mapper/luks-2ddd7768-d55b-4b7c-857d-d346505c3bed noiswmd 
LANG=en_US.UTF-8 SYSFONT=latarcyrheb-sun16 KEYBOARDTYPE=pc KEYTABLE=uk 
rhgb quiet
     initrd /initrd-2.6.32.8.img
However it doesn't work... after going through the password prompt for 
LVM decrypt I'm just left with a flashing cursor. Output of 
/var/log/messages points towards massive X display failures: "GDM 
Display lasted 0.080075 seconds". Xorg.log says that screens are found 
but none have a usable configuration.
What am I missing..? Could anyone assist please or point me towards a 
better way of doing things or how I can troubleshoot further? At this 
point in time everything has to be transferable via usb key...
Thanks,
Charlie