Activating hard mode throws this error:

Failed to load mods: BrassTacks-Updated/techfuncs.lua:44: Trying to add tech prereq: gyro({effects = {{recipe = "gyro"}}}) to tech: skyseeker-armature (nil)but one doesn't exist!
stack traceback:
[C]: in function 'error'
BrassTacks-Updated/techfuncs.lua:44: in function 'addPrereq'
BrassTacks-Updated/data-updates.lua:305: in main chunk

It's trying to add gyro tech prereq to skyseeker tech, but I don't have AAI Signal Transmission or SE installed, so it's bugging out. Don't know why it's triggering.

Might I add, that I already have gyroscopes from the BZ-silicon mod, but haven't ticked the "Brass Tacks override" in the settings. Maybe it's assuming override is ticked, even though it isn't, and is trying to reference Brass Tacks's prototype instead of BZ-silicon's?

EDIT: I can confirm that ticking the "override" allows the game to load normally. So the setting option isn't working as intended.