/dev/adc, /dev/leds. etc have disappeared?

After a number of teething troubles getting a working uboot, kernel and
JFFS2 image for my micro2440+SDK after I inadvertently erased the factory
image I now find that while I've got the thing booting to a prompt OK the
board specific /dev/ entries have gone. None of buttons, leds, pwm, adc,
etc. work any more - they did with the factory software loaded. Just doing
manual mknod's to create them is not sufficient to make them work.

Does anyone have any idea what might have occurred to cause this? I'm
assuming it must be differences in the .config of the kernel? Or could it
be something to do with the .ko's in the rootfs?

Cliff
(desparate for any suggestion!)

Cliff I solved this selecting udev option inside buildroot.

The udev is responsable to mount these devices.

To compile with buildroot I put the t35_mini2440 inside
archs/arm/configs directory and select to use defconfig inside buildroot
with the right name.

Best Regards.

You need 
mini2440_adc.c
mini2440_buttons.c
mini2440_leds.c
mini2440_pwm.c
files in kernel(\drivers\char) Check that they exist