This is often an MCU issue. You may need to upgrade the MCU firmware (part of the NWD package) rather than just the Android system image.
Open PhoenixSuit on your computer, navigate over to the Firmware tab , and select your target .img system file. k2001n nwd firmware work
: Look for a string similar to K2001N_NWD_S212B72 . This is often an MCU issue