built-in debugger - features not implemented?

[Duhhh]

I just fired up the built-in debugger (VB 4.1.6 on linux). I created a test program with an infinite loop, ran it in the vm, and broke in with the debugger. All seems fine. I can disassemble, dump registers, memory, etc. However, when I try to jump over the loop, by setting the guest eip, I get: VERR_NOT_IMPLEMENTED: DBGFR3RegNmSet failed settings 'eip'

Are there features of the debugger that are implemented as an add-on?

[Technologov]

Few developers here.
Better ask dev questions on vbox-dev mailing-list.
https://www.virtualbox.org/wiki/Mailing_lists