https://bugs.winehq.org/show_bug.cgi?id=50858
--- Comment #8 from Alexandre Julliard julliard@winehq.org --- (In reply to Roman Pišl from comment #7)
Another possibly related problem: wine "C:\windows\sysnative\rundll32.exe" wine: failed to open L"C:\windows\sysnative\rundll32.exe": c0000135
system32 and syswow64 work.
sysnative is a different issue. It has never been properly supported.