ipmitool -H 127.0.0.1 -U USER chassis bootdev
Password:
bootdev [clear-cmos=yes|no]
bootdev [options=help,…]
none : Do not change boot device order
pxe : Force PXE boot
disk : Force boot from default Hard-drive
safe : Force boot from default Hard-drive, request Safe Mode
diag : Force boot from Diagnostic Partition
cdrom : Force boot from CD/DVD
bios : Force boot into BIOS Setup
floppy: Force boot from Floppy/primary removable media

ipmitool -H 127.0.0.1 -U USER chassis bootdev pxe
Password:
Set Boot Device to pxe