As Shane Nay once pointed out, if you hose the PMON partition of your VR3's flash, you will have made a rather lovely brick. There's no going back if you screw up PMON. This is why should you write protect the PMON partition with the following instructions. This will prevent you from screwing up and accidentally making your VR3 permanently unusable. Please follow these instructions extremely carefully. First you have to get to the PMON prompt. Usually you do this by starting minicom, hyperterm, etc with the following settings: o Baud: 115200bps o Bits, parity, stop: 8N1 o Flow control: hardware or none Now reset your agenda, and hit ENTER within the first three seconds of the boot. You should then be at a PMON> prompt. Now you can enter the following commands to write protect or unprotect your PMON. ----------------------------------------------------------------- To WRITE PROTECT your PMON, these are the instructions: m -b bfc00000 60 m -b bfc00000 01 d -b bfc00000 (Should display 80 00 80 00, etc.) Type 'q' to stop the display m -b bfc00000 ff m -b bfc20000 60 m -b bfc20000 01 d -b bfc20000 (Should display 80 00 80 00, etc.) Type 'q' to stop the display m -b bfc20000 ff ----------------------------------------------------------------- To WRITE *UN*PROTECT your PMON, these are the instructions: NOTE: You should only unprotect PMON if you are about to flash upgrade the PMON binary on your Vr3. Otherwise, at all times, you should have PMON write protected so you don't accidentally brickify your VR3. m -b bfc00000 60 m -b bfc00000 D0 d -b bfc00000 (Should display 80 00 80 00, etc.) Type 'q' to stop the display m -b bfc00000 ff m -b bfc20000 60 m -b bfc20000 D0 d -b bfc20000 (Should display 80 00 80 00, etc.) Type 'q' to stop the display m -b bfc20000 ff ----------------------------------------------------------------- Lastly, here's the output from a session where I protected PMON using minicom. AFAIK, your output should be very close if not identical: PMON version 3.1.272 [NEC Vr41XX UEB,EL,FLASH] VR4181 support by Bradley D. LaRonde Mar 18 2001 13:58:05 This is free software, and comes with ABSOLUTELY NO WARRANTY, you are welcome to redistribute it without restriction. CPU type NEC VR4181 Rev 5.2. 65.54 MHz/1.17 MHz. Memory size 8 MB. Icache size 16 KB, 16/line Dcache size 8 KB, 16/line Autoboot command: "g -e bf0005e0 -- root=/dev/rom video=vr4181fb:xres:160,yres:" Press any key to cancel. 2 PMON> PMON> m -b bfc00000 60 PMON> m -b bfc00000 01 PMON> d -b bfc00000 bfc00000 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00010 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00020 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00030 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00040 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00050 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00060 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00070 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00080 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc00090 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ PMON> m -b bfc00000 ff PMON> m -b bfc20000 60 PMON> m -b bfc20000 01 PMON> d -b bfc20000 bfc20000 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20010 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20020 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20030 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20040 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20050 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20060 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20070 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20080 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ bfc20090 80 00 80 00 80 00 80 00 80 00 80 00 80 00 80 00 ................ PMON> PMON> m -b bfc20000 ff Good luck, Jeff