mSat in MacBook Pro

[TinMan77]

I've been using a 500Gb mSata SSD in my 2011 MacBook Pro for a year and half now. Its been the secondary drive for all this time but recently I've decided to make it bootable. The problem is I just can't seem to figure out how to do it. Please help!!!

 

[DeltaMac]

To make your secondary drive bootable:
You will just need to install macOS on your drive. Once that install is complete, it will boot to that drive, to complete the system install.
What version of macOS do you want to install?
What system is installed on your present boot drive? It's a simple matter to boot to your recovery system, and just choose to reinstall macOS, AND choose your mSATA drive as the destination for the system install.
Or, you can use a bootable USB installer to install macOS on your mSATA. This depends on what you need, and what you have now.

 

[TinMan77]

I have Sierra installed to my present boot drive. I've tried that but the MSATA drive doesn't show up in the list of drives when I boot to recovery mode