Hi @esos These ISO files booters are different from traditional booting.
You are trying to hard to focus on the past. I do not recommend using older PUPs before Dec 2019 for SG2D. I hope you focus on where PUPs are today as they continue to add support for new files system, new hardware while maintaining compatibility with as much older as is possible.
These 2 booters you reference DO NOT CHANGE any PUPs or DOGs.
@bigpup recommendation, I wholeheartedly agree with as once the PUP-DOG is booted to desktop, it may not have that Linux subsystem support built-in the PUP-DOG. ... FACT!. And @bigpup is clear that the exFAT support might not be built-into the PUP. That fact does not, though, interfere with the PUP's operation, nor does it introduce stability or system performance issues of any sort. He does NOT indicate that, either. PUP operations are exactly as the PUP developer produces.
These booter services do work and work well to boot ISO files, directly, while eliminating MANY of the issues newcomers and less experience users run into with USBs and the issues needed to build Frugals or FULL setup.
@esos you make this comment
... in my test it is not realy working "as if they are a Frugal installed PUP."
What evidence can you produce that support that claim by you? In my several years of observation, I find no such occurrence. If you have something please produce as there may be something that is deficient in a PUP. Let us examine what you have expressed, please.
Please be aware that these attempts at reducing boot issues across the board intend to allow any of us to go directly from ISO file downloaded, to booting to the ISO's desktop with no effort. The USB that a user builds, he does so ONLY ONCE in the USB's lifetime while he adds/deletes ISO file forever in the USB's future. No more issues related to creating media from an ISO/IMG download.
You may not like either of these, personally as they are rather new for us, but so far they are working well for what they do for us.
As mentioned in the forum, both of these boot services provide their own support, costing NO development time for PUP-DOG developers. Yes they provides simple solutions for seeing and booting the PUP-DOGs downloaded but at no expense to the community, at large.
AS is the case with everything, nothing is perfect. If you like what they offer, I'm sure you will take advantage for your needs. If its not a perfect match for you, as you mentioned, there are other ways to manage how and what you use to get your modern PUPs/DOGs to desktop. These are only 2 of them with little to no effort to boot a modern PUP-DOG.
Hope this helps. And, PLEASE, if you found a Frugal issue (major or minor), please share that.