The latest firmware for the BVA8051 is version ar18d, released back in 2005. You can find it on the
Leadtek FTP site.
A factory reset is performed as follows:
1. Unplug the power
2. Lift the handset of the phone off hook
3. Use a pin to push into the reset hole, hold it there while you plug the power back in, and you will see power LED flashing rapidly. Keep holding it until the power, link, activity, and line LEDs flash several times in alternating pairs to indicate that factory defaults are being restored.
The BVA8051is actually the same as the SIPphone Call-In-One adapter. I think SIPphone's documentation may be better that Leadtek's. There are some applicable PDF documents
HERE, Look for any PDF documents with names containing "8051" or "call-in-one".
The BVA8051 may not work with the updated FWD, but it can be used with Voxalot. Example setting for Voxalot are
HERE. I have a DTA310 with firmware AR17I, I was unable to make voice mail notification work. The problem may or may not have been fixed in firmware AR18D. For some reason I am not able to run firmware AR18D on my DTA310 device.