How to get and flash kernel seperately?

[siqui]

Hey,

my current System:
AV7500 with i-boot

I'm booting from usb right now. Though loading the kernel via usb takes a while i want to load it from the internal flash.
Currently i have kernel 207 in flash memory which boots just fine with an apropriate image (12***). After upgrading the image on the usb-stick, i want to upgrade the kernel in flash to version 215.

Could you please help me?
Where can i get the kernel only?
How can I write it to flash?

Best regards
Simon