Hello, I've done some "Re-chipping" with Chinese chip programmed to 20mm.
Just pulled out the flex cable in the lens from the pins on the rear side.
And soldered the chip underneath:
The AF don't works properly - it slow and in steps.
The exif shows 20mm, but the lens is recognizable like Minolta 100/2.8 Macro
There is Aperture Control, but the chip is programmed from f/1.4, not f/1.7, otherwise all Works.
There is SSS and Focus Confirmation.
That is for now.