id,summary,reporter,owner,description,type,status,component,version,resolution,keywords,cc,guest,host 17350,use of serial port crashes VM w/ non-mainstream OS,Ralph Schmieder,,"I try to run a Cisco router VM based on x86 known as IOSv (virtual IOS). The same image works perfectly fine with KVM and VMware Fusion / Workstation / ESXi. It also works OK in VB as long as there is no serial port connected. However, the serial console is the only way to access the box (assuming it does not have a configuration which also would allow to SSH / Telnet into the VM / router). When starting up the VM in VB it displays the Grub boot loader and then, in 9 out of 10 cases, instantly displays a Guru meditation instead of loading the kernel image. This is regardless of using a Pipe, a TCP port or a raw file for the port. Haven't tried host device as that's useless for our use case. If the port is enabled but 'disconnected' then the VM comes up fine all the time. This was tested on a Mac (MacBook Pro Mid2017, Intel Core i7) with - VB 5.1.30 - VB 5.0.40 - VB 5.2.2 I also ran into this problem on Linux. Here I run VB in a nested VM running on KVM on an Intel i7 w/ host-passthrough and 5.0.40 on Ubuntu Xenial... It seems to work more often there (more than 1 in 10) but also produces the Guru meditation when trying often enough. ",defect,new,uart,VirtualBox 5.1.30,,,,other,Mac OS X