The system uses flash PROMs to permit the reprogramming of specific code blocks that are held in non-volatile system memory, and to permit remote reprogramming of that code by an authorized system administrator over a local area network.
Two jumpers, J2703 and J2804, on the main logic board affect flash PROM operation. The default shunt setting of J2703 is on pins 1 and 2. Placing a shunt on pins 2 and 3 enables reprogramming of the flash PROM.
When you reprogram NVRAM, it stores the old program in the high half of NVRAM as a backup copy, in case something goes wrong in the new program. The jumper switches enable you to select which half of NVRAM you want to boot from: the low-half (or normal, default) or the high-half. This means that you can set the jumpers to select either "high-half booting" or "low-half booting."
Complete these tasks:
Locate the jumpers on the main logic board.
A main logic board jumper is identified by its jumper address, labeled on the board with the letter "J" followed by four numbers (JXXXX). Jumper pins are located immediately adjacent to the jumper address. On the board, pin 1 is marked with an asterisk.
For information about jumper locations, see "3.15 How to Set the Serial Port Jumpers".
Set the main logic board jumpers J2703 and J2804.
Using long-nose pliers, place a shunt over the appropriate pins according to the following table.
Flash PROM jumper |
A shunt on pins 1 and 2 selects |
A shunt on pins 2 and 3 selects |
The default shunt is on pins |
Signal that is controlled |
---|---|---|---|---|
J2703 |
Write-protect |
Write-enable |
1 and 2 |
FLASH PROM PROG ENABLE |
J2804 |
High-half booting |
Normal (low-half) booting |
2 and 3 |
XOR LOGIC SET |
Complete the following task to reassemble the system: