The reason why your system reboots normally instead of waking up from hibernate, is most likely that the configuration file “/etc/initramfs-tools/conf.d/resume” is missing the proper path to your swap partition.
To modify (or create) the proper resume entry and updating your system to reflect the changes, do the following.
Go into a terminal and switch on root access, by typing: “sudo -s” and entering your password. Then CD to the directory “/conf.d” mentioned above, and check if the file “resume” is missing. If it’s missing, create and save a new file (plain text) using the command “gedit resume” to edit or create the file.
The file “resume” must contain the text “RESUME=UUID=” + the actual UUID for your swap partition (locate it by viewing information on your swap partition using GParted). For instance my own configuration file lists (an example): “RESUME=UUID=79647610-c76d-4220-8c58-b4b9c71f9ead”. Yours should reflect the UUID that your own swap partition has.
Then save the “resume” file and check if it reflects the proper information, and use this command to update the system so that your changes is reflected: “update-initramfs -u”, alternatively “sudo update-initramfs -u” (the -u stands for update).
After this has been done, your system knowns the proper location to your swap partition and thus the proper location to wake up your system from hibernate properly.