Unfortunately, you are wrong. The link above says: "This BIOS update is for Intel NUC Kit DE3815TYHE with the SA number H27002-500 and later and for Intel® NUC Board DE3815TYBE with the AA number H26998-500 and later." What is a SA / AA number read here: https://www.intel.com/content/www/us/en/support/articles/000005804/mini-pcs.html
You can find the BIOS for the earlier DE3815TY NUCs at https://downloadcenter.intel.com/download/29053/BIOS-Update-TYBYT10H-86A-. It looks like this record was flagged incorrectly, so didn't appear in search results on Download Center. We'll get that fixed right away.
thanks for the answer. however, it was after installing this BIOS that the board overloaded loaded. This is not surprising - the description says that - "for Intel® NUC Board DE3815TYBE with the following AA numbers: H26998-401, -402, -403, -404, and -405." And I have AA H26998-200 ...
H26998-200 is an early unsupported pre-production sample. Unfortunately, Intel doesn't support those with either technical or warranty support. While the BIOS version I mentioned should work, debugging a problem on a sample unit isn't possible.
I installed this version of BIOS (https://downloadcenter.intel.com/download/29053/BIOS-Update-TYBYT10H-86A-) and the board does not load now. Unfortunately, I did not save the old version of BIOS, and now I can not use the recovery procedure. You do not have earlier versions of BIOS for the recovery procedure?