Unhelpful feedback "DrvVD: Configuration error: keys incorrect at level 0"

[krichter]

Starting a VM which formerly worked fine fails due to

    DrvVD: Configuration error: keys incorrect at level 0 (VERR_PDM_DRVINS_UNKNOWN_CFG_VALUES).
    AHCI: Failed to attach drive to Port0 (VERR_PDM_DRVINS_UNKNOWN_CFG_VALUES).


    Fehlercode:
    NS_ERROR_FAILURE (0x80004005)
    Komponente:
    ConsoleWrap
    Interface:
    IConsole {872da645-4a9b-1727-bee2-5585105b9eed}

displayed in dialog after start. It'd be helpful to know what failure occurred for what reason and what are useful steps to proceed. It looks like an error in the configuration file, but it's just too useless to guess if you could improve the feedback.

experienced on Ubuntu 16.10 host with Gentoo guest

[krichter]

This is caused by an errornous directive

    <ExtraDataItem name="VBoxInternal/Devices/ahci/0/LUN#0/Config/IgnoreFlsh" value="0"/>

which should be

    <ExtraDataItem name="VBoxInternal/Devices/ahci/0/LUN#0/Config/IgnoreFlush" value="0"/>

so it'd be useful to tell the user that instead of providing internal information which only VirtualBox devs can understand.

Is it wise/necessary that VBoxManage setextradata doesn't fail when setting these errornous values.