I downloaded the kernel, factory, and upgrade files for the WRT3200ACM. The problem is that Edge wanted to block the factory.img file but not the other.bin files. It had the warning that the file is malicious and confirmed downloading.
If you're referring to this Microsoft Defender SmartScreen warning that your file isn't commonly downloaded, I get that all the time when downloading FOSS apps for Windows.
As above, if you're concerned about anything malicious you can upload your file to VirusTotal, but as long as it comes back clean then I don't think you have anything to worry about.