1、EDL

Note: FORCE_USB_BOOT forces the device to enter EDL regardless of boot configuration. It can be enabled by
changing the switch position of FORCE_USB_BOOT GPIO pin or grounding USB D+ pin. FORCE_USB_BOOT is
scanned at PBL, and USB D+ is scanned at SBL.

USB Force Factory Download

Uses the switch to pull D+ to GND and power
on the device; it runs to EDL when it detects
D+ is low in SBL1.
▪ Disconnects the switch. D+ recovers to normal
and continue to enumerate the PID 9008 port.
Use this port to download the software. VBUS
always stays on during the process.