Linux can boot Linux via kexec. There is no way to boot the disk's bootloader without going through the bios.
1.just bootup Harddisk in Kernel at tc@box:~$ seems no way for now .
>>Thanks for saving the researching time from deeply and wide world.
thanks again.
2.exit kernel and send some flag then go back to isolinux boot: auto check flag & "localboot -1"
Here is some idea regarding for item#2
if it possible to add a function in isolinux boot . example as below in Quote:
Force_Default_Remain_CountDown = 1 set in kernel . and when next BIOS boot to USB isolinux boot . it
will Force boot from "localboot -1". then HHD bootup.
It means Next USB boot will still back to USB's tinycore kernel to perform the USB Key by password sync again.
Force_Default_Remain_CountDown back to
zero and take default is label "
1".
display boot.msg
default 1
# Boot other devices
label 0
localboot -1
Force_Default_Remain_CountDown = 1
# USB BOOT
label 1
kernel /boot/vmlinuz
append initrd=/boot/core.gz loglevel=3
implicit 0
prompt 1
timeout 0
F1 boot.msg
F2 f2
F3 f3
F4 f4