【AGPTEK】M20 Firmware Upgrade

For customers who bought this player manufactured on or after July 1st, 2018. (To know when your player is produced, please check the Series No. which is located on the back of the player with numbers and letters. For example, A000180701B, the manufacturing date is 80701, which means it is produced on July 1st, 2018.)
Warning: Before the serial numbers:20180701, customers should not update this firmware. Otherwise it will not be able to boot.
Updated on July 7th, 2018

Add bookmark function under Music submenu
Enable to hold the middle(play) button to stop playing when the screen is off and unlocked; hold the +/- button to go to next/previous song; click +/- button to increase/decrease the volume
Change the operation duration from 10 seconds to 60 seconds when holding the left / right button to fast forward / rewind.