move wrkeyupload to a post-flash procedure

avoid deploying boxes which fail booting in certain conditions because of
weird post-production processes >:-)
add (non-functional) UNION_FS enable config
Tailor Linux Kernel a bit more to our needs

* improve DBG behavior for rtl8981es driver
* disable memory allocation for v4l2
Update HP2 BLOB

Blob update.

- Several minor fixes:
Wifi scans on boot properly.
HP 'ups' interface on scanning for aps.
WRCService starts on boot if enabled.
Fixed WRC button.