sbl_v2_3_93e8 SBL v2 created on 7/26/2018.  Change to disable Encap OTA Support.
              SBL_v2 Release candidate #2. Header version 3

sbl_v3_4_994c SBL v3 created on 2/19/2019.  Adds IOS SPI and I2C support.
              Header version 4.

