Hi Dr. Chubb,

Thank you for your response. I tried it, but when the boot process hangs after as shown in the following. (I did not delete the default kernel in MMC)



U-Boot 2018.03-rc3-00090-g3990c9d (Mar 01 2018 - 14:33:40 -0500)

TEGRA124
Model: Colorado Engineering TK1-SOM
Board: CEI tk1-som
DRAM:  2 GiB
MMC:   sdhci@700b0400: 1, sdhci@700b0600: 0
Loading Environment from MMC... OK
In: serial
Out:   serial
Err:   serial
Net:   No ethernet found.
Hit any key to stop autoboot:  0
Card did not respond to voltage select!
switch to partitions #0, OK
mmc0(part 0) is current device
Scanning mmc 0:1...
Found /boot/extlinux/extlinux.conf
Retrieving file: /boot/extlinux/extlinux.conf
839 bytes read in 139 ms (5.9 KiB/s)
Jetson-TK1 eMMC boot options
1:   primary kernel
Enter choice: 1:     primary kernel
Retrieving file: /boot/zImage
6090032 bytes read in 187 ms (31.1 MiB/s)
append: console=ttyS0,115200n8 console=tty1 no_console_suspend=1 lp0_vec=2064@0xf46ff000 mem=2015M@2048M mem=6144M@4096M memtype=1 ddr_die=2048M@2048M ddr_die=6144M@4096M vmalloc=300M section=256M pmuboard=0x0177:0x0000:0x02:0x43:0x00 tsec=32M@3913M otf_key=c75e5bb91eb3bd947560357b64422f85 usbcore.old_scheme_first=1 core_edp_mv=1150 core_edp_ma=4000 tegraid=40.1.1.0.0 debug_uartport=lsport,3 power_supply=Adapter modem_id=0 android.kerneltype=normal fbcon=map:1 commchip_id=0 usb_port_owner_info=2 lane_owner_info=1 emc_max_dvfs=0 touch_id=0@0 board_info=0x0177:0x0000:0x02:0x43:0x00 root=/dev/mmcblk0p1 rw rootwait tegraboot=sdmmc gpt
Retrieving file: /boot/tegra124-tk1-som-pm375-000-c00-00.dtb
57253 bytes read in 274 ms (203.1 KiB/s)
## Flattened Device Tree blob at 82000000
  Booting using the fdt blob at 0x82000000
  Using Device Tree in place at 82000000, end 82010fa4

Starting kernel ...



Best Regards
-Daniel Wang



On Oct 10, 2018, at 11:30 PM, <Peter.Chubb@data61.csiro.au> <Peter.Chubb@data61.csiro.au> wrote:

Hi Daniel,
  You shouldn't have to reflash to boot the original Linux.  If you
  want to, use Nvidia's L4T tool.  But try to reset the secure mode
  booting by doing
     setenv bootm_boot_mode sec
     saveenv
  at the u-boot prompt.  This should enable the original kernel to
  boot.

Peter C
--
Dr Peter Chubb         Tel: +61 2 9490 5852      http://ts.data61.csiro.au/
Trustworthy Systems Group                     Data61, CSIRO (formerly NICTA)