Then reboot the Juno it should find the root filesystem using NFS. Power up the Juno board and interrupt U-Boot's default boot selection: The default boot selection will start in 3 seconds. VExpress64# set bootargs "console=ttyAMA0,115200n8 root=/dev/nfs ip=dhcp nfsroot=$:/export/juno/fs rw rootwait earlyprintk=pl011,0x7ff80000 debug" Next modify U-Boot's boot args to find the root filesystem using NFS: VExpress64# set origbootargs "$bootargs" Save your host PC's IP address to the `serverip' environment variable: VExpress64# set serverip Power up the Juno board and interrupt U-Boot's default boot selection: The default boot selection will start in 3 seconds In this example we extracted the root filesystem to `/export/juno/fs/'. Next extract your desired root filesystem into the `/export/' directory, optionally placing it in a subdirectory. This variable can be defined statically in U-Boot environment as follow: NAONsetenv bootargs 'root/dev/mmcblk0p1 rw consolettyO0,115200n8 earlyprintk mem176M vram46M notifyk.vpssm3sva0xBF900000' NAONsaveenv Saving Environment to SPI Flash. Now check that `portmapper', `nfs', and `mountd' are all running on both `tcp' and `udp': # rpcinfo -p U-Boot uses its bootargs environment variable as parameter. Then restart the `nfs-kernel-server' service: # service nfs-kernel-server restart # To disable nfsv4 on the server, specify `-no-nfs-version 4' here Set the default to NFSv3 by editing `/etc/default/nfs-kernel-server' as shown: # Number of servers to start up To avoid potential file permission problems we will avoid using NFSv4. Set the permissions of the hosted filesystem but adding the following line to file `/etc/exports': /export/ *(rw,nohide,insecure,no_subtree_check,async,no_root_squash) 2 Other Variscite U-Boot features 2.1 Automatic Device Tree selection. U-Boot now supports USB also on DART-MX6 SOMs. SD card is mmc 0, and eMMC is mmc1, like in all of our boards.
U boot bootargs install#
Install the following packages on your host PC: $ sudo apt-get update & sudo apt-get install nfs-kernel-server rpcbindĬreate a root `/export/' directory that we will use to host the filesystem: # mkdir /export/ U-Boot now supports both SD card and eMMC at the same time, also on DART-MX6 SOMs, regardless of where you boot from.
U boot bootargs how to#
See this page for instructions on how to TFTP boot the Linux kernel using U-Boot. If using Juno, ensure you are using the front ethernet port. This tutorial assumes your host PC is running Ubuntu 14.04.1 LTS or later and is on the same local network as your development platform for simplicity's sake we assume a DHCP server is available on the network, too.