Failsafe Boot Block Rom - Compaq Deskpro EN Series Maintenance & Service Manual

FailSafe Boot Block ROM

The FailSafe Boot Block ROM allows for system recovery in the unlikely event of a ROM flash
failure, for example, if a power failure occurs during a ROM upgrade. The Boot Block is a flash-
protected section of the ROM that checks to validate the system ROM each time power to the
system is turned on.
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If the system ROM is valid, the system starts normally.
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If the system ROM fails the validation check, the FailSafe Boot Block ROM provides
enough support to start the system from a ROMPaq diskette, which will program the
system ROM with a valid image.
Because there is no video or hard drive support from the Boot Block ROM, the keyboard lights
communicate information. When the Boot Block detects an invalid system ROM, the system
sounds a series of beeps (one long and three short) and flashes the three keyboard lights.
To recover the system after hearing the FailSafe Boot Block beeps, complete the following steps:
1. Remove any diskettes from the diskette drive and turn off the power.
2. Insert a ROMPaq diskette into the diskette drive.
3. Turn on power to the system.
If a setup password has been established, the Caps Lock light will turn on.
4. Enter the setup password.
If the system successfully starts from the diskette and successfully reprograms the ROM, then
the three keyboard lights will turn on. A "rising tone" series of beeps also signals successful
completion.
Compaq Deskpro EN Series of Personal Computers 2-25