booting from network requires a ramdisk with network modules (F4: netboot.txt)
(use command changeramdisk inside SPBLinux to add modules to file ramdisk)


root=[tftp|ftp|http]:[//][server[:port][/directory]]

tftp, ftp: if server is not given, server ip is taken from dhcp:
next-server entry of dhcp server; if not given, ip address of dhcp server.

Default directory is /spblinux (http,ftp) or PXEClient/spblinux (tftp)


root=[cifs|...]://server/share[/dir[/subdir]][:port]
root=[nfs|...]:server:/sharedir[/sharesubdir[:[/]/dir[/subdir]]]

Files are loaded, inside share, from directory [/dir[/subdir]]/spblinux
(with cifs/nfs subdirectory /spblinux is always appended; unlike tftp/ftp/http)


root=nbd:server:port

Network block device mount: files are loaded from /spblinux.