The firmware's support for GIMX has changed

[Fama-Lan]

Firmware versions before 1.4.2 can have force feedback after converting from GIMX to G29, but subsequent versions do not have force feedback. What is the reason for this and can it be resolved?

[Ultrawipf]

Since then pretty much everything has changed so i assume it does not support certain HID descriptor structures or it handles axis directions incorrectly. It could be pretty much anything and it is difficult to guess what difference causes incompatibility.
I heard of users who had similar setups with new firmwares that it should work so it might also be something on the configuration or gimx side instead.

What you can try is to compile it using the FFBWHEEL_USE_1AXIS_DESC definition which will use a descriptor that only defines 1 ffb capable axis.
Normally it presents itself as a 2 axis ffb device even in wheel mode which is more compatible in my experience.