I hope this post reaches to ISOMorphic Tool devs somehow...
So, I downloaded ISOMorphic Tool Build 187 from from sk65205. Btw, please, put the version and the build somewhere on the UI because it is nearly impossible to see what you are using without diving deep into the the exe file properties.
What I found is, the tool will only allow TGZ and GZ packages to be imported as hotfix while latest JHF for R81 are released as TAR files (look at sk170114 for example). I tried to compress and gzip the file but nevertheless the tool is rejecting it claiming it is not cpuse offline package.
Anyway, this is insane and shall be fixed asap! 😉