Why cant I boot from other boot image than the original? HTC

[oernii]

Hi, i have flashed 3 images on my rooted desire:

• the original backed up image
• splitted & recreated boot image with the same kernel and initrd as the original boot img
• boot image extracted from update-cm-6.0.0-N1-RC3-signed

Only the first image boots up, the other 2 do not even start on adb logcat. I have to reflash the original to boot up. This is what I do in recovery:

# ./split_bootimg.pl  boot.img
# mkbootimg  --kernel boot.img-kernel --ramdisk boot.img-ramdisk.gz --cmdline 'no_console_suspend=1' -o newboot.img
# adb push newboot.img /sdcard 
# cat /dev/zero > /dev/mtd/mtd2
# flash_image boot /sdcard/newboot.img

this does not boot up. If I flash the original boot.img however, it goes up.