: After an update, you often need an internet connection to reactivate ZLink.
: If sound disappears after an update, check the Factory Settings under the "AMP" or "Audio" options to ensure the correct output is enabled.
: If your unit is from a known brand, check the Joying Firmware Blog or Dasaita Support first.
: Some users share verified firmware versions via Google Drive links hosted on community forums like XDA Developers . How to Update Your CVD1810-WJ Unit
: If your unit doesn't detect the file, try creating a folder structure on the USB: mnt/media_rw/udisk/ and place the update.zip there.