Before updating, you must identify your existing firmware. Unfortunately, the VG421WDV2 does not have a "display firmware version" command over I2C/SPI by default. You need to use one of these methods:
If you are experiencing timing glitches, poor low-temperature startup, or high power consumption on your VG421WDV2, upgrading to the 2021 firmware is the single most effective hardware improvement you can make. Follow the flashing guide carefully, always back up your original firmware, and enjoy a ghost-free, energy-efficient display. vg421wdv2 firmware 2021
The firmware updates released in were not cosmetic. Manufacturers addressed three critical hardware-software bottlenecks. If you are still running factory firmware from 2018–2019, you are missing out on substantial improvements. Before updating, you must identify your existing firmware