bbb flashing emmc from sdcard and kernel upgrage


I’m trying to upgrade the kernel on emmc.
my steps:

  1. download image for bbb with Kernel: 3.8.13-bone72 (07/28/2015)
  2. flash sdcard
  3. branch build kernel 3.8.13-bone72 with some modifications on usb gadget (patch)
  4. run script ./tools/install to upgrade sdcard
    5.1. when bbb start with and uEnv.txt flasher I am getting panic error, also getting this error without modification on fresh rebuilded kernel (3.8.13-bone72)
    5.2. when try start bbb without flasher I can successfully boot from sdcard
    5.3. after running from bbb /opt/scripts/tools/emmc/ flashing completes, but running bbb from emmc hangs on startup (only showing penguin logo and cursor blinking no output from kernel debug)

please can someone help me with this issue.

simplified question
How to upgrade or is it possible to upgrade newly custom kernel to the eMMC image (debian 7.8 from 2015-07-28 with 3.8.13-bone72)?

best regards