Try a different USB port (preferably a USB 2.0 port on the back of the motherboard) as some firmware tools are picky about USB 3.0/3.1 speeds.

: Flashing a new firmware version can result in data loss. Always back up your data before proceeding.

cm69update.bin typically refers to a firmware update file for budget-friendly dash cams or generic electronics (often based on the Novatek chipset). Whether it is "better" depends entirely on your current hardware version; installing the wrong firmware can "brick" your device (render it unfunctional).

: Always ensure a full system backup is stored externally.

: Ensure your device is fully charged and in a stable state. Boot into recovery mode (usually by pressing a combination of buttons like Volume Down + Power).

Are you comparing it to a previous version (like cm68) or a different modded firmware?

One of the biggest headaches on the J7 Prime development scene was data encryption. Many custom ROMs failed to encrypt the device properly, or the user couldn't access internal storage via TWRP.