Most of the questions here are about creating a live/installation bootable USB key, but what I need is different and I can't find an answer.
I have a Linux installation on the hard drive, which, after installing Windows 10, is (obviously) not bootable. "Start with a liveCD and reinstall grub" I hear you say, but I don't want to do that: I don't want to install grub because the Linux installation is only temporary. What I need is really just a way to boot (once or twice, to run some tests) into the Linux partition. I'm pretty sure what I have to do is start from a LiveCD and enter some custom boot parameters, but I'm pretty ignorant in the matter so I have no idea what the command line should look like. Help please!