Issues with OS update via USB Stick

I have a profiler that has OS 3.3x and I am trying to update to the latest from the website, 5.1x. It appears that I can't use a new enough PC software to the the update via PC, I must use a USB stick. I have tried two different sticks, my unit recognizes them, formats them correctly, and I can back up rigs to the USB stick. However, copying over the KAOS.BIN file to either the Operating System folder or root folder and re-inserting into kemper and I never get a notification to update the OS -- I have tried booting with it in, inserting it when it is in browse mode, etc nothing works. I have tried powering up with EXIT depressed and attempting to run directly from the USB drive with KAOS.BIN in the root directory -- it tells me that the file is invalid. I found one very old forum thread where someone had an identical problem, but there was no resolution posted. Anyone had this come up? Fix?

Thanks!

For those that may encounter this problem (probably not many since newer units are shipping with OS that can be updated by rig manager), I found that copying over files using mac instead of PC worked for me. I am certain that I followed all best practices and the only change was the computer used to copy the files. I am not saying PCs are incompatible, but clearly there was an issue with the particular PC I was using.

Quote from paults

Have you tried re-downloading the OS file? Maybe the file IS invalid.

Yep I tried that and I also tried multiple OS files (beta and released) just in case. No dice. Very strange.

Quote from mnewse614

I use a mac so may be different, but after I formatted my usb I had first added all the files into the the os folder and it didnt work, I went back deleted everything from the os folder and copied and pasted the 1 kaos file inserted it and it immediately worked. Not sure but I would just make sure there is just the one file in the os folder

Yep I tried every combination you could think of, I am a computer savvy person so I believe I followed all best practices.... What worked for me was switching from that particular PC to my MAC. I may try it again on a different PC I have just to debug when I get the time, maybe next time I upgrade and I will report back.