Chosen Solution
I didn’t find any upgrade kit for 2017 iMacs. I know for 21.5 SSD-only iMacs, there should be a standard SATA connector at the back of the logic board, but what about the power? Which power cable should I use? Also where should I get the rubber bumper? Any help is appreciated!!
I agree with @mayer - I would wait until your warranty has expired. I also think you can get a better solution externally than adding in an internal 2.5" drive. Just so you can see how much work it is review this IFIXIT guide: iMac Intel 21.5" Retina 4K Display (2017) Logic Board Replacement You’ll need to get to Step61 so you can plug in the SATA & power cable on the back side of the logic board. As far as the needed parts you can use the older 2015 SATA & power cables Apple is using the same cables here. The rubber cups are different which will be difficult to get presently.
