Go to Settings > About > Software Version to confirm the new firmware installed correctly.
Installing a stable, optimized firmware—specifically —via an SD card is the "top" way to revive a sluggish MXQ Pro 4K Go to product viewer dialog for this item. mxq pro 4k firmware 71 2 download sd card top
To update your MXQ Pro 4K to firmware 7.1.2 using an SD card: Go to Settings > About > Software Version