HiFive U RiscV-pc alpha release

Alpha release supporting U-boot to replace FSBL, and a mostly functional RiscV PC with the Microsemi expansion board.

The '.gpt' image file can be used to flash U-boot on the SPI flash, as documented in the HiFive Unleashed getting started guide, or can be written directly to the SDcard with DD on a linux system.

We currently recommend you leave MSEL2 in the 'outward' (marked on) position to load U-boot from the SDcard unless you are a uboot developer.

SHA 256 checksum of .gpt file is:
2542ae1e90840524263f3842c1458e21c47a372ea37b36e7cb12989360375032 hifive-unleashed-a00-2019-03-22.gpt