U3
VL805
IC
USB 3.0 controller
About this component
Connected to the BCM2711 over a single PCIe Gen 2 lane, so all four USB-A ports share about 4 Gbit/s. Early Pi 4 boards keep its firmware in a separate small EEPROM, while later revisions load it from the main bootloader EEPROM. If all four USB-A ports are dead but USB-C and Ethernet work, check its firmware (rpi-eeprom) before suspecting the chip.
What it does on this board
VIA USB host controller feeding the USB ports.
Pinout & readings
No pinout or reference readings yet — these show what each pin does and what a healthy part should measure.