switch between NFS boot and eMMC boot

G’day All,

I have modified the uEnv.txt on the eMMC so that I can boot via network (NFS) or uSD (using invalid uboot command). My question is: once you boot via NFS or uSD into Linux, how can you mount and access the eMMC so that the uEnv.txt on eMMC can be modified to boot from eMMC again? I could reflash the eMMC but that is really an overkill and time-consuming as I have to switch from eMMC and NFS booting often.

Any suggestions? Thanks

sudo mount /dev/mmcblk0p1 disk


Thanks Robert for the quickly reply.

However I should have mentioned that the real issue I got was I could find partition /dev/mmcblk0p1 once boot via NFS or uSD.

root@beaglebone:~# ls /dev/m* -la
crw-r----T 1 root kmem 1, 1 Jan 1 2000 /dev/mem

Not sure it is peculiar to my board (NFS boot into ubuntu 14.04.1).

But anyway I sorted it out by getting into uboot. In case any one else gets into the same trouble, I post back the steps I used to switch NFS boot back to eMMC boot:

  1. Hook serial console and space bar into uboot
  2. type “boot” and ctrl-C while it is NFS booting is loading files (still loads the modified uEnv.txt)
  3. recover the original uenvcmd by
    set uenvcmd ‘run loadfiles; run mmcargs; bootz ${loadaddr} ${initrd_addr}:${initrd_size} ${fdtaddr}’
  4. run uenvcmd to boot via eMMC

Once booted, /boot/uboot/uEnv.txt can be edited from there.

Note: my uEnv.txt used for NFS booting only got extra defs on top of original uEnv.txt), hence step 2 can set up all the variables.