1st I want to recomment you, if you haven't already, to take a look into theinks IPac2 Guide

@joshrdunstan said in IPAC-2 causes Dual Button Press:

My IPAC-2 is an early version, pre 2015. I note that there is a firmware that allows an IPAC-2 to come up on the pi as 2 peripherals - however I can't figure out how - or if - I can update the firmware. When I hit the update firmware button on WINIPAC (V1) it just says "Download started" but doesn't appear to do anything.

citing Ultimarc

Latest firmware files (ver 1.55) for all 2015-onwards I-PAC, Mini-PAC and J-PAC boards plus all Ultimate I/O boards regardless of date. NOTE: Attempting to upgrade a pre-2015 board which this firmware will render it inoperable.

Link for Pre2015 Boards (from linked side above) [edit: No Firmware, just utils as it seem]

Hi, I seem to have the issue that's somewhat documented, where the IPAC-2 I have configured in ES on initial startup, is now causing some double button presses where there's a conflict on what is configured in ES and what's configured in retroarch.cfg. It makes most of the games on MAME unplayable. Both the configured joypad input plus the raw keyboard press are being sent to the emulator.

That's because Mame is recieving the "Keys" from the IPac-2 "Keyboard" together with the "Gamepad-Buttons" from the virtual RetroArch-"Retropad". Depending on the mame core you are using, there is either the possibility from within the retroarch-ui to configure the input mame will recieve, or for cores where that is not possible, the only way I am aware of is to configure the Input via the mame menu using either a real keyboard/gamepad and assigning only real kbd keys or gamepad keys to the functions (or by editing the corresponding .ini (edit: <default>.cfg) by hand (via editor of choice).

Lr-vice