Hello everyone, I'm working on Rockchip rk3399 Nanopc t4 board and I'm trying get serial output from board using minicom and my board has baudrate 1500000. I'm using a usb to serial converter. So, when i power on my board minicom starts to give junk characters. Minicom version: 2.7.1 USB driver probed : cp210x But when I use the same setup with my colleagues laptop it gives correct output (kernel version 4.15.0-52-generic ). Note that my colleague and i used same setup Same usb driver probed Same power adapter same usb to serial converter wire same minicom version. same baudrate Other thing which i tried is switching kernel version and it turns out that one of the older distro kernel on my system (debian 4.9.0-5-amd64 ) is working fine and it seems like there is something changed in newer kernel vesions. Here is the quick summary 4.19.0-4-amd64 -> not working 4.15.0-52-generic -> working 4.9.0-5-amd64 -> working 5.2.0-rc4+ -> not working Did anyone else faced the similar problem. Is there any patch available if it is bug ? Please let me know. Thanks a lot, Shyam