i downloaded the kernel source from webos opensource website then patched it,
used arch/arm/configs/omap_sirlion_3430_defconfig as .config,
then make && make uImage, used the uImage which is located in arch/arm/boot
tellbootie recover to make pre+ into recovery mode, then novacom boot mem:// < uImage.
After long booting, the pre+ successfully ran into webos, but when i cat /proc/version, the content is shown as below

Linux version 2.6.24-palm-joplin-3430 (na@na) (gcc version 4.2.1 (codeSourcery Sourcery G++ Lite 2007q3-51)) #1 281.1.23.2

the compiler i use is (Sourcery G++ Lite 2011.03-42) 4.5.2

so i doubted that pre+ did not load my kernel?But i do not know why.