Updating System Firmware to 15.41.0.0 totally kills my ethernet internet connection

[DWSR]

In checking Windows Updates, I found that an "optional" System Firmware" update 15.41.0.0 was available. I usually do not install any "optional" updates but, for some unknown reason, I decided to install this one. That was a BIG mistake! The installation completely successfully but required a re-boot. Immediately after re-booting, I noticed that I could not connect to the internet. An "undefined" public network was created with no internet availability on both of my ethernet ports (one was built-in directly to my PC, the other was created with a USB-to-Ethernet adapter).

Does anyone know what the previous firmware version to 15.41.0.0 was? I do not suppose that there is any way to downgrade the firmware back to its previous version! Is there???

I also had problems connecting to my Synology DS220+ NAS but finally got it working again. While my NAS was not working, I used my earliest available "restore point". Unfortunately, my earliest restore point was the day "after" I installed the firmware update, so it did not help. In fact, it caused me more problems.

Now that I got my NAS working again, it contains a lot of backups, including many earlier than the firmware update date. I have now started to try one of those earlier backups. However, to accomplish this, I have to boot from a "recovery" USB. So far, I have not been able to get that USB to boot the system. I am very definitely trying to avoid doing a full factory reset, I've got way too much software I'd have to reinstall. It does NOT look good.

Has anyone, with the same PC I have, installed that optional firmware (15.41.0.0)? If so, did it work for you? If not, did you have problems similar to mine? Any ideas? (By the way, I also spent several hours on the phone a few days ago talking to HP's "SmartFriend" paid support. The tech assured me that he could solve the problem but was totally unable to do so.)