Before you start, make sure you have everything ready:
The speed of your USB drive matters. While the PS2's port is slow, a cheap, slow flash drive can make things even worse. Use a known brand (SanDisk, Samsung, Kingston) with good random read speeds. A high-quality USB 2.0 or 3.0 drive (backward compatible) is ideal. usbutil v21 ultimate for ps2 usb mode 2 link