hello, I bought two nucleo F401RE, MB1136 rev C. I run Windows XP sp3. On first one I upgraded the firmare to version v2j23m6 with STW-LINK007, apparently with success (no errors in Windows Device Manager, ST-Link Utility recognizes the device and shows the firmware version). But virtual com port is not working (nucleo_printf online compiler example program). I also tried serial UART 1 and 6 with an external uart-usb adapter, with no success. On the other hand, the second board, which I did not updated, works fine. St-link utility reports firmware v2j19m3 on it. I couldn't find that firmware on site site; I found STSW-link005 with v2j21m5, and also St-link utility makes update to that, but with this update the situation is unchanged. How can I revert to the old firmware? or what can I do? Thank you in advance, and please forgive me for my shaky english. Paolo

Hi Paolo, have you installed manually the ST Link Driver/V2 before upgrading the firmware? If not I suggest you to uninstall every piece of driver and software inherent the board and driver. Please refer to this page for a complete list of instruction and links to the necessary files an installer: https://developer.mbed.org/teams/ST/wiki/Nucleo-Firmware Let me know if this works for you.

Best regards