As promised I worked on the Amiga OS 4 problem in Lazarus Cross Amiga Docker. I tried to used vlink and vasm for it, but it seems vlink has some problems with the resources. But when switching back to the GNU tools (as and ld) it again works.
I also added a little Updater Script to the archive, so if you want to use the new Amiga OS 4 download again the archive. Start the script ./CheckForUpdate.sh if there is a newer version of the docker it will automatically download.