The full sentence is:
This license allows you to install or operate the AmigaOS only on a computer system that had a version of AmigaOS installed on it at the time you acquired such computer system, which was especially prepared for running AmigaOS through the use of a dedicated (flash)rom or similar mechanism or for which a legitimate version of AmigaOS was or is available.
Do you read the above as 2 types of systems, or 3 types of systems (do you have an implied "or" or an implied "and" before the "which was especially prepared")?
What is your understanding of "a legitimate version of AmigaOS"? Is a kickstart ROM enough?
What is a "similar mechanism" - is a kickstart file on an SD card a "similar mechanism"?
Does Hyperion consider Cloanto distributions of kickstart/workbench, and licenses of thereof (for example sold with MiST and Minimig), "legitimate"?
"And" I'd say. The comma, as used in this statement, indicates that the following is a continuation of the previous part of the sentence. In this case a further clarification of the previous part. So "which" refers back to "AmigaOS".
My understanding is that Kickstart alone does not constitute the AmigaOS. As they say the flash(rom) only prepares the computer to run the AmigaOS.
"Similar method", not being further specified, seems to imply a physical item, not solely digital. An SD card, being a type of flash memory, should fall within the description although since it is technically flash RAM and not ROM it could be argued that it does not. A Kickstart image on a mechanical hard drive may not but on an SSD would. It really depends on the technical meaning of the word "similar" from a legal standpoint. I am not a lawyer nor do I portray one on TV so I don't know enough to answer that
For "legitimate" I would have to say that it depends entirely on the terms of the license from Hyperion that the reseller is granted distribution. Without being able to see the license I doubt we could decide. It's probably also going to be subject to the outcome of lawsuits like the ongoing cases between Cloanto and Hyperion. That particular situation, as I understand it, is over several issues - ownership of things and distribution / reselling rights.