boot modifier and special notes for the operation
Boot Modifier Keys
To boot from SD card, the Letux 400 U-Boot checks that Fn + Left-Shift are pressed on power up.
After Initial Boot
The kernel recognizes additional modifiers to switch the root file system. These are different from the combination used by U-Boot and are interpreted by a routine provided in the kernel.
You can press these additional keys right before pressing the power button but must hold them at least 5 seconds. They are not checked immediately after power on when the penguin appears but with more delay.
If you see the "INIT: version 2.86 booting" message on the screen, you can release the buttons. Here are the modifier keys:
- F1: boot from first SD partition (/dev/mmcblk0p1, ext3)
- F2: boot from second SD partition (/dev/mmcblk0p2, ext3)
- F3: boot minifs from internal partition (/dev/mtdblock3, jffs2)
- F4: boot from internal partition (/dev/mtdblock4, yaffs2)
- Fn: boot from second SD partition (/dev/mmcblk0p2, ext3) (kernel was booted from SD on Fn+Ctrl+LeftShift)
- none: boot from internal partition (/dev/mtdblock4, yaffs2)
WARNING: Don't press Fn + Left-Shift + Ctrl to boot! This will copy the 2.6 kernel into the NAND flash and afterwards, you can't boot from NAND to the original system. To recover from such a mistake, please refer to http://download.goldelico.com/letux-400-jtag/