Log message:
Install only the useful files, and install *all* of the useful files.
Bump version to 2019.04-rc4nb2.

Log message:
- Update to u-boot-2019.04-rc4, which works much better on the
  MediaTek mt7623 SoC than the previous 2019.01-rc2.
- Pull down the necessary SDMMC binary headers and preloader from BPI's
  Github repository, and use them to assemble an image that can be written
  directly to an SD card before adding an MBR partition table.

Log message:
U-Boot is a bootloader for embedded boards based on PowerPC, ARM, MIPS and
several other processors, which can be installed in a boot ROM and used to
initialize and test the hardware or to download and run application code.

This package provides U-Boot for the Sinovoip Banana Pi BPI-R2.