Your ROOT_URL in app.ini is https://src.whiteboxsystems.nl/ but you are visiting http://src.whiteboxsystems.nl/Whitebox/u-boot/src/commit/782b97805e9f59cc2b4d3aa67a8a03248e8cd722/doc/SPI/README.altera_spi
You should set ROOT_URL correctly, otherwise the web may not work correctly.
SoCFPGA EPCS/EPCQx1 mini howto: - Instantiate EPCS/EPCQx1 Serial flash controller in QSys and rebuild - The controller base address is the "Base" in QSys + 0x400 - Set MSEL[4:0]=10010 (AS Standard) - Load the bitstream into FPGA, enable bridges - Only then will the driver work