He made copies—DD images of the boot and recovery partitions—onto an external drive. That safety net felt prudent: if anything went wrong he could at least restore the original firmware. He also wrote down the device’s serial and printed the vendor’s update image format. The key realization: many H616-based devices used U-Boot and Allwinner’s FEL/burn tools for recovery and flashing, which meant development would require a Linux host and some low-level flashing utilities.