When running on JDK9+ Byteman installs a read link from the module it uses to give itself privileged access to the unnamed module containing the rest of the Byteman classes. In default operation that module belongs to the system loader, allowing Byteman to access private fields of classes in the CLASSPATH. If Byteman is hoisted into the bootstrap path then that module belongs to the boot loader, allowing Byteman to access private fields of public classes in the bootstrap path but rendering it unable to access private fields of classes loaded by the platform or system loader. The required fix is for Byteman to add read edges to the unnamed module of these two loaders when it is in the bootstrap path i.e. when the loader of its own non-module classes is null.