just as you find it in the(now) many descriptions. only ad a -k to the line.

the way i do it is
(this is only the kernel)
flasher-3.5 -f -k kernelimage -R

kernel in a fiasko you need the big F
flasher-3.5 -F <firmware-image> --flash-only=kernel -f -R
(the -R is to reboot)


a hint:
they always say press the "u" button and have the phone waiting with the usb symbol and after that use the flash utility.
while that is perfectly ok i found reversed order is easier to handle.
so as a hint: first go to your pc and type the whole flasher line in and press enter. now it will say that it has no device and is waiting for a device to appear. keep it in this state. let it wait as long as you need for the phone. that way you have plenty of time(as long as it takes) to fiddle with your device to get it in the state needed. you usually don't even have to press the u button just let it boot connected with the pc as the utility is eager waiting for the momment to flash the phone and will do it as soon as it is possible.


EDIT: do as many backups as you can. never leave a chance out to do a backup. better safe than sorry!