Hi Ivan,
I’m glad to know others are having the same problems and it is not just us - it’s just unfortunate that no-one seems to be willing to help get this situation resolved.
I am not familiar with the .wpk files, however we downgraded our modems using R7.47.6_sl6087.dwl successfully and it resolved our issues - it’s just we had to do it on 50 Modems!!
Any firmware below 7.5 worked correctly for us, and we stopped getting the CME Error 10.
I hope this helps.