*              0000 - Error
 *              0001 - Not used
 *
 *      Original Pi boards:
 *              0002 - Model B,  Rev 1,   256MB, Egoman
 *              0003 - Model B,  Rev 1.1, 256MB, Egoman, Fuses/D14 removed.
 *
 *      Newer Pi's with remapped GPIO:
 *              0004 - Model B,  Rev 1.2, 256MB, Sony
 *              0005 - Model B,  Rev 1.2, 256MB, Egomnn
 *              0006 - Model B,  Rev 1.2, 256MB, Egoman
 *
 *              0007 - Model A,  Rev 1.2, 256MB, Egoman
 *              0008 - Model A,  Rev 1.2, 256MB, Sony
 *              0009 - Model A,  Rev 1.2, 256MB, Egoman
 *
 *              000d - Model B,  Rev 1.2, 512MB, Egoman (Red Pi, Blue Pi?)
 *              000e - Model B,  Rev 1.2, 512MB, Sony
 *              000f - Model B,  Rev 1.2, 512MB, Egoman
 *
 *              0010 - Model B+, Rev 1.2, 512MB, Sony
 *              0013 - Model B+  Rev 1.2, 512MB, Embest
 *              0016 - Model B+  Rev 1.2, 512MB, Sony
 *              0019 - Model B+  Rev 1.2, 512MB, Egoman
 *
 *              0011 - Pi CM,    Rev 1.1, 512MB, Sony
 *              0014 - Pi CM,    Rev 1.1, 512MB, Embest
 *              0017 - Pi CM,    Rev 1.1, 512MB, Sony
 *              001a - Pi CM,    Rev 1.1, 512MB, Egoman
 *
 *              0012 - Model A+  Rev 1.1, 256MB, Sony
 *              0015 - Model A+  Rev 1.1, 256MB, Embest
 *              0018 - Model A+  Rev 1.1, 256MB, Sony
 *              001b - Model A+  Rev 1.1, 256MB, Egoman
 *
 *      A small thorn is the olde style overvolting - that will add in
 *              1000000
 *
 *      The Pi compute module has an revision of 0011 or 0014 - since we only
 *      check the last digit, then it's 1, therefore it'll default to not 2 or
 *      3 for a Rev 1, so will appear as a Rev 2. This is fine for the most part, but
 *      we'll properly detect the Compute Module later and adjust accordingly.
 *
 * And then things changed with the introduction of the v2...
 *
 * For Pi v2 and subsequent models - e.g. the Zero:
 *
 *   [USER:8] [NEW:1] [MEMSIZE:3] [MANUFACTURER:4] [PROCESSOR:4] [TYPE:8] [REV:4]
 *   NEW          23: will be 1 for the new scheme, 0 for the old scheme
 *   MEMSIZE      20: 0=256M 1=512M 2=1G
 *   MANUFACTURER 16: 0=SONY 1=EGOMAN 2=EMBEST
 *   PROCESSOR    12: 0=2835 1=2836
 *   TYPE         04: 0=MODELA 1=MODELB 2=MODELA+ 3=MODELB+ 4=Pi2 MODEL B 5=ALPHA 6=CM
 *   REV          00: 0=REV0 1=REV1 2=REV2