The Arria10 SoCFPGA can boot from multiple sources: SD Card, NAND flash, QSPI flash and eMMC, that can be selected via the BSEL pins. If the bootrom can not find a valid bootloader on that medium, it will fall back to JTAG. So for developing and testing, the BSEL pins can just be set to a medium that is non-existent. In case of bootstrapping, the bootrom falls back to JTAG anyway, as there is no valid bootloader, yet.
A BSP (Board Support Package) in Embedded Software is the layer of software that lets you run your application on a specific hardware. For Pengutronix a BSP usually contains a bootloader, Linux Kernel and a userspace. DistroKit is our Demo-BSP that supports a variety of common evaluation boards. DistroKit gives you a head start if you want to develop an application on top of such an evaluation board with most of the hard problems already solved.
One of our projects required the addition of board support for the Digi ConnectCore 6UL SBC Pro to the Barebox bootloader. This article outlines the used development setup and required additions to the bootloader to support a board with a well supported processor. Development of the board support was done live during the monthly talks at Stratum 0, the hackerspace in Braunschweig. The video (in German) is embedded at the end of the article.