I have the X-T3 and have been working (fighting) with Ekos / Indi trying to make things work.

I have discovered:
1. Force Bulb = OFF
2. Camera set to ES (electronic shutter), Shutter speed dial set to "B", ISO dial set to "A", focus selector to Manual, "Shoot without lens" = ON, Camera's PC Connection Mode set to "USB tether shooting auto".

I am shooting RAW, uncompressed files.

I am able to use the camera via Ekos / Indi to make exposure sequences. (but only using shutter speeds that the camera is capable of - the Indi driver only supports certain shutter speed despite what the Ekos Camera Module drop down box shows. e.g. setting 7 seconds causes the camera/driver/?? to fault require (in my case) a reset of the Raspberry Pi that runs the system. (I found a list of "supported" shutter speeds in the Debug log produced by KStars.

Hope this helps you a bit.

I don't know whether the X-T1 has these settings available in it's menus or not.

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