I recall now that the HDD based Hexic HD files are
enclosed in a
PIRS container, and do not actually exist as separate files on the X360 HDD. Thus the default.xex Flash player need not checksum the Hexic SWF itself as the
signed PIRS archive already does this.

The files within the PIRS archive, including the default.xex and the SWF, can be extracted (see
PIRSTOOLS and
here for the results), and could be placed back on the X360 HDD (necessary due to the default.xexs HDD media flag!), but then we'd still need a method to launch the HDD-located default.xex Flash player (for which no technique is yet known

).
(No way currently exists to rebuild and correctly sign our own PIRS files!)It would appears that M$ intends that all downloadable executable content be enclosed in PIRS containers, as precious few actual XEX files appear on the HDD - Only 2, IIRC - both to do with running the XBOX1 backwards compatibility support. I guess we could replace one of those 2 XEXs with the HDD Flash player XEX, and see if attempting to run a legacy XBOX1 invokes it.

That does put a damper on things. Will xex run outside the pirs container? I haven't been keeping track of some of these developments. At least you can still decompile the deluxe hexic. So why hasn't it been documentated yet?