PMON
From LinuxMIPS
PMON is a freeware ROM-monitor developed for early LSI Logic MIPS R3000 evaluation boards. Since its creation, PMON has become a very common firmware for MIPS evaluation boards and development systems.
For information on PMON, visit Phil Bunce's (PMON's designer) website at http://www.carmel.com/pmon .
The PMON code base is rather old now, supports relatively few boards and is not being actively worked on by a single project team. PMON 2000 has become the inofficial successor of PMON.
There is a PMON-VR fork for the NEC_VR4100 as part of the Agenda VR3 HPC project.