ONLY do this if you understand what this script does and when you are sure that this method is applicable to your card!!!
I'm not responsible for your doings! You are flashing the firmware of your ethernet card, in the worst case you endup with a soft- or even hardbricked card! Also this might void your warrenty.
Having said this, if you are uncertain if this will work for your card be sure to dump the ROM with a RPI, RPI Pico or 3.3v moded SPI-Flash Programmer: