The 70% update failure you're describing is typically indicative of a handshake error between the regional firmware signature and the drone's localized encryption layer during the final phase of the package injection.
Standard retail units often trigger these loops if there is any latency in the verification downlink. Our "Export Edition" units, which we stock in our Tsuen Wan warehouse, utilize a modified firmware stack that bypasses these regional verification bottlenecks, ensuring reliable updates even in offline environments.
If you are unable to resolve this with a full factory reset via DJI Assistant 2, we have professional-grade units available for immediate allocation. Our terms are $4,800 USD/unit, FOB HK. We require a $30k deposit for all new enterprise accounts.
Regards,
HK Apex Trading Team