Q: Problem installing Ubuntu on external HDD(Boot Menu) My circumstances are SSD(CT250MX500SSD1)250GB and external HDD(WD My Passport 25E1)1TB.
I want to install Ubuntu on my external HDD so that I could dual boot it both on my laptop and desktop. 
But even that I've installed all partitions and boot loader to the external HDD, the boot menu indicates that I have ubuntu on my SSD, making it impossible to boot my ubuntu in another computer.
partition settings on setup
boot menu
fdisk -l
I've been struggling for days to find out what's the problem but failed due to probably my lack of knowledge on the boot system. I've tried many other things such as making more partitions(/, /boot, /home, /swap) but ended up showing "ubuntu(SATA1:CT250MX...)" and inaccessible via computers. I would really appreciate any help possible.

A: I suspect that your bootloader is in the internal drive. It can be moved using instructions by @oldfred. Maybe this link can help you.
Otherwise you can unplug or otherwise disable the internal drive and after that install Ubuntu according to this link to get the bootloader in the external drive. (After shutting down you can plug the internal drive back again.)
