Updating the kernel of a running system
As an install step, the Linux kernel (with BBL) can always be written on the host card reader. However, for regular use, it is inconvenient to keep swapping the card between devices. If you already have a running Linux system, perhaps based on the pre-made executables, it is possible to replace the kernel in the running system, which saves wear and tear from regularly swapping cards between target system and PC. To use this method proceed as follows:
On the target system there will already be a pre-made non-privileged user called lowrisc.
Generate a public key (optional, but more convenient if you don’t already have one):
ssh-keygen -t rsa
On the host (first time only, if you have a public key):
ssh-copy-id lowrisc@192.168.0.51 # substitute your boards' own IP address
On the host:
sftp lowrisc@192.168.0.51 # substitute your boards' own IP address
lcd lowrisc-quickstart
put boot.bin
quit
On the target system, logged in as root, proceed as follows:
mv ~lowrisc/boot.bin /mnt/dos # ignore error about preserving ownership
halt
You cannot upload directly to the DOS filing system because it does not support credentials so only root can write to it normally, and root login via sftp is disabled for security reasons. After the final shutdown message is printed, the reset button may be used to reboot.
Next recommended step: