I have a HP R5500 XR UPS with a Management Card. In order to update the firmware for the UPS itself (I.e., not the management cards f/w) one has to connect, via a serial cable, to the management card and enable Pass-Thru mode so as the serial port connects directly to the UPS.
I have done this and successfully updated the firmware, but I was wondering if there was a way to exit Pass-Thru mode without manually resetting the Management Card using the reset pin. In the past I've always done it manually, but this is a remote box so it's more of a hassle.
The answer to this appears to be simple: No!