topic Re: USB start failed in Uboot in i.MX Processors

USB start failed in Uboot

rahul_raja — Thu, 10 Jul 2025 05:15:15 GMT

Hi,

I have flashed the i.MX8M Mini board and interrupted the boot process to access the U-Boot prompt. However, when I run the usb start command, I receive the following output

u-boot=> usb start
starting USB...
Bus usb@32e40000: Port not available.
Bus usb@32e50000: Port not available.

It seems that the USB ports are not being detected or initialized correctly in U-Boot. I need to access USB functionality from U-Boot for further testing. Could you please guide me on how to debug or resolve this issue?

Looking forward to your suggestions.

Re: USB start failed in Uboot

Rita_Wang — Tue, 15 Jul 2025 02:49:05 GMT

Which version BSP are you using? And which boot device you boot up from here, SD card or emmc?

Re: USB start failed in Uboot

rahul_raja — Tue, 15 Jul 2025 04:37:04 GMT

BSP Version: Yocto Scarthgap (6.6.52)
Boot Device: SD Card

Additional Information:

I have modified the U-Boot Device Tree Source (DTS) file by setting dr_mode = "host" for the usbotg2 node (usb@32e50000). Following this change, the USB controller at usb@32e50000 is now functional and successfully detecting connected USB devices.

However, the USB controller at usb@32e40000 (usbotg1) is still experiencing detection issues. The current configuration for usbotg1 has dr_mode = "otg".

Looking forward to your suggestion

Re: USB start failed in Uboot

Rita_Wang — Mon, 21 Jul 2025 07:46:39 GMT

How about your design, usb1 work as otg and usb2 work as host? Which usb interface are you using, type-C or micro usb?

Re: USB start failed in Uboot

rahul_raja — Tue, 22 Jul 2025 05:06:39 GMT

Yes, our design configures USB1 to work as OTG and USB2 to function as host and also using micro usb

Re: USB start failed in Uboot

Rita_Wang — Wed, 23 Jul 2025 02:21:55 GMT

You modify the usb2 setting may not affect the USB1 in generally, are you changing in the board dts file or chip dts file?