You are welcome. I can netinstall that board for sure, but still - I wish to know that what caused this issue was fixed, so probably I do not encounter that on any other board upgrades. I didn't use netinstall utility. I used Webfig interface in the browser. I had to spent several days with that rou...

I've also experienced the same problems with RB751U-2HnD RouterOS upgrade to 7.1.1. But after that also I couldn't downgrade back to 6.49.2 Stable. But I finally solved this problem! I downloaded 6.48.6 Long-term MIPSBE all_packages-mipsbe-6.48.6.zip and unpacked from there ONLY necessary packages: ...