Hi, another strange thing is, after some bootups (i boot kernel from tftp, but also on full power cycle), musb-driver maps musb-hdrc.4.auto instead of #1 root@bpi-r2:~# dmesg | grep musb [ 5.502914] musb-hdrc musb-hdrc.4.auto: MUSB HDRC host driver [ 5.508782] musb-hdrc musb-hdrc.4.auto: new USB bus registered, assigned bus number 5 and then nothing works (no roleswitch, no power which does not work with pinctl / without regulator). It's hard to test if things working before, do no more work if device is named differently. maybe Min Guo can help here? after bootup mode is b_idle in my case (currently do not change if i connect otg cable) root@bpi-r2:~# cat /sys/devices/platform/11200000.usb/musb-hdrc.4.auto/mode b_idle regards Frank