i just bought two teensy 4.1 to prototype for a project of mine, that maybe i will sell in the future.
If all works out i was thinking to design the electronic on a single board, and just buy your bootloader.
When the teensy 4.1 arrived it did with the linked text that i can’t use it in commercial product essentially.
Is this true? Is the only bootloader subject of the same conditions?
Because that would be a problem for me and would change the vision i have on using teensy
The units are subject to that paragraph; they are not to be re-sold :-/
And that’s ok, those will just be my way to approach the microcontroller and check for the connection to be right, after this they would become just hobby microcontroller of mine.
I was talking about, is the bootloader part of the teensy, bought alone just to be soldered on a pcb subject of the same paragraph?
It’s not the bootloader that has export controls, it’s the processor chip on the board that does. You can not resell the board to certain countries without breaking federal law.
What countries are currently on the restricted list, as defined by the U.S. government?
Cuba, North Korea, Sudan, Syria, Iran, Russia, Belarus, and specific regions of Ukraine (Crimea, Donetsk, and Luhansk)
See the page at the link below for more info.
Export Compliance - SparkFun Electronics Export Compliance - SparkFun Electronics
As long as your product doesn’t go to those places you should be fine but you should consult a lawyer before selling your export controlled product, the consequences ate pretty severe if your product finds it’s way to the wrong place.
so the problem is given by the NPX iMXRT1062 on it? if i went to a bare pcb this chip would give the same problem?
Yes, that is the processor and the part that is export controlled.
So even just using this chip is a problem? 
It says in the invoice that i need permission from the USA to even make it change hands
The blurb essentially means the purchaser (which is you) needs to be the end-user (which is you, for hobby purposes?)…otherwise obtain special permission. If you aren’t re-selling or shipping it to somewhere else, ostensibly you should be good. If you are doing either of those things you should consult an attorney.
But just using it is fine 
doesn’t seem a nice thing for people who wanna make a product out of it, having to consult an attorney for the ones i already got there is no problem cause i was gonna use them for myself, but if i need to get special permissions i think it’s gonna get me to take another route on the microcontroller side. 
To be fair, these rules apply to anything that’s export controlled under U.S. law, not just the Teensy.
You’re going to run into this time & again during your commercial product development.
Those little fineprint cards we discard, Read Before Use decals we peel off a display, and checkboxes we mindlessly click have tons of language about what is and isn’t yours and mine and theirs. The sticking point is that all of those are written so as apply to the End User: An OEM’s license to OP does not, in general, automatically extend or transfer to the OP’s customers and is, for this particular discussion in particular, explicitly disallowed.
Here, it further appears that may be overarching Governmental export constraints which are probably best considered impossible to get around.
