Does Latitude 6430u read and write SDHX or UHC-I SD cards?

Does anyone know for certain what the card reader in the 6430u is capable of?

Given the smaller SSDs I'm limited to by Dell's use of non-conventional mSATA drives for this machine, I was hoping to at least keep a high-capacity (SDXC) card for archive storage in the reader. 

But I cannot find a spec sheet anywhere that tells me what formats are supported by the built-in card reader.
I contacted ProSupport, but got the sense the tech there was not familiar with the 6430u and just reading from a script when they said:

Here are the specs for your 6430U
Cards supported SD/SDIO/MMC/MMC+/SDHC/xD (Type M/M+/H)

Surely this is not the case, is it?  Could Dell really be including such utterly obsolete hardware in such a new model?

The SDHX & UHS-I formats came out under version 3.0, which was released in January, 2009 - 5 YEARS AGO! 
Heck, version 4.0, supporting UHS-II has been around now for 2.5 years, since June 2011.

If that's really the case, is there perhaps a firmware upgrade or hack or replacement part that might allow me to have additional on-board storage?

I'd also love to know exactly what the card readers in my old E6410 or Inspiron 620 mid-tower desktop are capable of reading or writing to.  But alas, there don't seem to be spec sheets that spell those out, either.

Thanks,
Ed