Beyond the Basics - BeagleBone - page 280

Discussion
This is the same screen command as in Recipe 5.4 , just using a different port.
TIP
To see and save the boot loader and Linux boot-up messages, press ^AH (Ctrl-A and then H) to
start logging to a file on your host computer and then reboot your Bone.
Now you see what goes on before the kernel starts:
bone# reboot
Broadcast message from root@beaglebone (ttyO0) (Thu Jun 19 15:04:40 20
The system is going down for reboot NOW!
...
[ 368.405404] Restarting system.
U-Boot SPL 2013.04-dirty (Jul 10 2013 - 14:02:53)
...
reading u-boot.img
U-Boot 2013.04-dirty (Jul 10 2013 - 14:02:53)
I2C: ready
DRAM: 512 MiB
WARNING: Caches not enabled
NAND: No NAND device found!!!
0 MiB
MMC: OMAP SD/MMC: 0, OMAP SD/MMC: 1
*** Warning - readenv() failed, using default environment
...
Hit any key to stop autoboot: 1 ... 0
gpio: pin 53 (gpio 53) value is 1
mmc0 is current device
micro SD card found
mmc0 is current device
gpio: pin 54 (gpio 54) value is 1
SD/MMC found on device 0
reading uEnv.txt
1672 bytes read in 7 ms (232.4 KiB/s)