I realize I sound like a noob above, I didn't make the distinction between packaging (ie tar) and changing a binary into an update installer. After reading the python src and the scripts I understand what is going on. I never read this because I skipped the ss stuff (since it is non-functional, as a priority). I found the update packager script at v0.13 here
https://www.mobileread.com/forums/sho...te+tool&page=7 and successfully packaged it, then used the k3g, but to no effect, still the same U007 error. I have to run out now but later I may see if I can grep U007 in the source code for better understanding. I am also going to try installing some other update packages to see if I have the same problem. Do you have any other ideas?
Thanks for your help