The VP-X manual recommends using a backup battery for the EFIS, so that you can see the fault on the EFIS circuit if it occurs. Alternately, you can connect the VP-X configurator. Glad it worked out for you.
If you continue to get flap runaway fault then the flaps are not configured correctly. There is a lot of good detail in the install manual about how to correctly configure the flaps.
RV-7 980 hours, IO-390, VP-X (sold)
RV-8 (flying a friend's)
Thinking about low and slow backcountry build.
VAF Advertiser - Aircraft Wiring Guide
Book to help with experimental aircraft wiring.