Just installed the decathlon cable for a fork mount light at the front. Waiting for a clamp for the crown as don't want to drill.
Is this the light for the rear?
https://www.lite-move.com/product/ts-rk-litemove/
Just thought I'd update this old thread as I'd been looking for exactly the same cable to connect the Marquardt controller to an Iphone.
On ebay there is a "iPhone to DJI Mavic Mini/2/Air/Spark Remote Control 29cm Data Cable Adapter" which does the job as I tried it out today.