Just downgrade to rebug 3.55.3, then install firmware 3.15, or 3.16. Do not install 3.17, it should be fakeware.
You can not downgrade from version 3.56+ directly, cause old pkg key was revoked/replaced.
So you have to install 3.55 fw with spkg support. Rebug 3.55.3 would be OK.
Then you can go...