Sorry if this is off-topic, but I have searched in Google and I cannot find an answer to this issue, or a hint to diagnose it further. I have compiled a 3.5.6-1 kernel for a MCUZONE (www.mcuzone.com) board with a Fedora 17 armv5tel userspace. This particular board has two physical serial ports, of a maximum of three supported. The board boots with the kernel commandline: console=ttyS2,115200n8 root=/dev/mmcblk0p2 rw rootwait ip=off . This results in systemd starting a serial console login with agetty in ttyS2, as normal and expected. For usability reasons, I want to run a second serial login in ttyS1. I therefore ran "systemctl start 'serial-getty(a)ttyS1.service'", and the agetty starts. However, it will not complete the login process. It will show the banner and the login: prompt. I then type the user (say, "root"), and then it asks for the password, which I type correctly, but then it complains "Inicio de sesión incorrecto" (Login incorrect). To rule out serial communication issues, I attached strace to each agetty in ttyS2 (working) and ttyS1 (not working), and both receive the username (one character at a time), and then the password (as a single string followed by \n). So I am at a loss about why ttyS2 works and ttyS1 does not. As far as I can tell with strace, both instances receive the username and the password correctly. What can I do to diagnose this further? Do I need to modify something else to enable the second login tty?