I mean, "uname -m" gives you information about the kernel, not about the hardware. If "uname -m" says "i686" it means that your kernels is 32-bit (or pretends¹

I mean, "uname -m" gives you information about the kernel, not about the hardware. If "uname -m" says "i686" it means that your kernels is 32-bit (or pretends¹ to be so). It doesn't necessarily mean that your hardware is not capable of running a 64-bit kernel. So unless I'm missing something, the above procedure does not work correctly. Instead, you should run something like this: $ lscpu | grep -w mode CPU op-mode(s): 32-bit, 64-bit ¹ http://man7.org/linux/man-pages/man8/i386.8.html http://man7.org/linux/man-pages/man8/i386.8.html