I’d like to up quite old topic (here was the link on the topic but I can’t attach links forum engine says)
I just have the same problem with fresh 25.04.2.6
I decided to go deeper and to find the solution.
First of all I started embedded EFI shell to try to run loader manually and there I got no luck there with message for example “fs0:\EFI is not a directory” after I tried cd to it, though dir fs0:\EFI shows that it is directory 
Then I installed a fresh debian on a next drive to ensure it starts perfectly in the same conditions.
Next I started to compare different things and (with help of AI of cause) found that TrueNAS’es ESP has 512 Bytes logical sector size whereas the Debian’s one has 4096 Bytes. The same AI claims it found that early instances of UEFI work badly with 512 Bytes logical sector size.
Next I backup a content of ESP, reformat it “right” way and put al the files back.And yes, it helped, now I have wokring system the way I want.
So the main question is why TrueNAS changed the default (and obviously well-tested) Debian’s scheme to the new one, were there some reasons for that or it happened accidentially so?And the second one is where can I put the corresponding issue, where is the right GH repo (if any)?
You should have got an introductory email. Take the tutorial by the TrueNAS Bot and view a few other forum posts and you should be able to post links and images.
Well I haven’t got actually since I signed up through my GitHub account not my e-mail
And I still nave not idea what should I do to attach the link
Click My messages on the left-side navbar in the forum. You should have a Greetings! or welcome message from truenas-bot that has the first tutorial message in it. Otherwise I think you can comment @truenas-bot start tutorial anywhere and it will message you.