This message was posted on behalf of Intel Corporation
sw01: Thank you very much for joining the Intel® NUC communities.
We are sorry to hear the BIOS update was not working properly, but we are glad to hear that the NUC is working fine now. In regard to your inquiry, there are no reports stating that there is a boot problem with the Intel® NUC Kit NUC6i7KYK on BIOS 0048 or 0049. We do have the same NUC in our lab with BIOS version 0049, and it works without any problems.
The troubleshoot step we recommend to try to fix this issue, is actually what you did, which is a BIOS recovery.
Additionally, on the link below you will find the released notes for the different BIOS versions created for this NUC, in there you can verify the fixes for each version:
I also encourage all the peers viewing this forum, that if they have any feedback or suggestions on this matter to post all the details on this thread.
Any further questions, please let me know.