First, make sure you have correctly connected the USB Male A to Dupont Cable to the board’s pin 14, pin 16, and pin 18.
If the connection is correct, press and hold the recovery button on the board (located on the bottom side beneath the Ethernet port) before powering on the board. Once powered on, your computer should recognize a Maskrom device.
Depending on your operating system, refer to the following documentation to choose the appropriate flashing method:
Loader used for flashing: rk3328_loader_ddr333_v1.16.250.bin.zip (177.9 KB)