I started off by installing the full version Kali Linux on a USB drive. I went through the graphical installer and repartitioned the USB with /home and swap partitions so this isn't a Live USB, just to clarify. Now onto my issue.
If I boot up my Macbook Pro (2015) with the USB plugged in, I boot straight into the Kali install. If I unplug the USB and boot up the Macbook, it boots into MacOS without any issues. However, if I plug that same USB into another Macbook, I am not able to boot into Kali. Even if I go into the Startup Manager, I am not given Kali as a boot option, and this Startup Manager issue happens on all Macbooks I have tried.
This situation makes me believe that during the initial Kali install, the boot loader (or boot partition, I'm not 100% sure here) on that Macbook was altered which is why it is the only one able to boot into Kali. I am wondering if it is possible to alter the boot partition and use EFI on the USB drive with Kali on it to allow booting from the Startup Manager on any Mac device. And if it is possible, what are the steps I would need to take to achieve this?
What I Have Tried So Far
I attempted to follow the steps in this article but was unsuccessful because I wasn't able to install the PPA mentioned since Kali doesn't allow PPAs to be used for compatibility issues (this could be a solution if anyone knows how to get around this).
1) Is it possible to alter the boot partition on a USB install of Kali and use EFI to allow booting from the Startup Manager on any Mac device. And if it is possible, what are the steps I would need to take to achieve this?
2) Is it possible to get around PPA restrictions on Kali because that could potentially allow to resolve the issue in question one?