This DGK6X code is shared between the ANSI variants of Venus, Hades and Galaxy keyboards.
Instructions for building the Venus, Hades and Galaxy firmware can be found here:
For first Flashing from initial Stock's Firmware
Using dfu-util:
dfu-util --list
dfu-util --alt 0 --dfuse-address 0x08000000 --upload ${OLD_STOCK_BIN}
Using QMK Toolbox
Using dfu-util:
dfu-util --alt 0 --dfuse-address 0x08000000 --download ${NEW_QMK_BIN}
You can short Boot0 to Vdd by shorting R19 to C30 on the sides closest to the processor, as shown:
Hades & Venus:
Galaxy 75
For repeating Flashing you can use BootMagic: