Solaris

Please note: This solution does require some soldering ability.

If, like me today, you really really need to get into OpenBoot on a non booting Solaris machine (in my case an Ultra 5) but your USB dongle won't send <BREAK> then here is a -really- simple hardware hack that works a treat:

<BREAK> is not actually a valid character in RS232 - it's actually a hardware generated positive pulse which most USB to serial dongles can't produce.

It is really simple to build a lead that provides this pulse which forces the machine into its boot monitor. The user then simply reconnects the serial dongle and finds himself at the OpenBoot prompt.

Parts required:

9 volt PP3 battery
PP3 battery clip with red and black wires
1K resistor
9 Way male Sub D Connector
Preferably also a backshell for the connector

Solder one end of the resistor to pin 3 on the D connector
Solder the red lead of the PP3 clip to the other end of the resistor.
It is advisable to insulate the above connection with some electrical tape or some heat shrink sleaving.
Solder the black lead to pin 5 on the D connector.
Fit the backshell to the D connector to protect the cable

Its worth testing the lead using a multimeter if you have one:

Connect the battery, place the red multimeter probe on pin red and the black on pin 5. There should be around 8-9 volts.

To Use:

Start the Solaris machine up with the USB dongle connected using your preferred terminal program. Once it's clear the machine is starting up then unplug the serial lead from your USB dongle and plug in the battery lead for a 2-3 seconds. Unplug the battery lead and plug the serial dongle back in and after hitting return a couple of times you should be in OpenBoot.

The resistor is to prevent damage by drastically reducing the current - never simply wire the battery directly to pins 5 and 3.

This solution works a treat on all my older Sun kit.

USERS BUILD THIS LEAD AT THEIR OWN RISK - I TAKE NO RESPONSIBILITY FOR SMOKED SERIAL PORTS.

Dan.