This is a preemptive question to avoid problems.
I currently use a desktop PC with one hard drive in a caddy and one internal HDD (they both are SATA drives); the internal 1 TB drive is just for data with no OS on it (formated as NTFS so that both windows and linux can read and write to it). As a boot drive (to be inserted into the caddy) I have several HDDs with 1 or more OS on them:
2 with Windows XP only.
1 with Windows XP and Linux Mint.
1 with Windows 7 and Linux Zorin.
When I want to use Win7 or Zorin, I put the specific HDD in the caddy and switch on the PC; If I want to use Win XP or Mint, I switch off the PC, take out the drive and put in the other drive (with XP or Mint), and switch back on the PC.
All that works flawlessly at the moment because all the drives are formatted in legacy mode with an MBR and the boot information is on the drive. But soon I will have to upgrade (or replace) the computer and I will need to use UEFI and GPT. I want to continue using caddies and multiple HDDs (of course I will have to re-install them under uefi on the new computer), but from what I have read so far on various forums, I will have some problem when changing HDD as under UEFI some of the boot instructions are written to the motherboard chip and I think it gets overwritten each time I install a new OS on to an other HDD, so only the OS/s that have been installed on the last HDD will boot. All the previous OSs on the previously installed HDDs will not boot as the system does not see them as bootable drives or something else is missing (i'm just guessing here, I'm not sure exactly why or how)
Is this correct? Does anyone on this forum run a similar system and could share their experiences? And if my information is correct, is there a way around it?
For example would it be possible to put all the boot information on each HDD only? (Only the information for the OS/s that is/are on this specific hard drive would needed to be present).
I hope I explained the setup well enough to be understood. Thanks