DE10 Advance Board Setup: MSEL Settings
From Terasic Wiki
FPPx32 Mode (Default)
The FPGA Configuration Mode Switch (MSEL) shown in Figure 2-1 is by default set to 001 (MSEL [2:0] = 001). The setting corresponds to FPGA configured from HPS software (in the SD Card) in FPP mode. If users want to boot with Linux VNC desktop, please setting MSEL switch in this mode.
AS Mode
When the board is powered on and MSEL [2:0] is set to “010” (See Figure 2-2), the FPGA is configured from EPCQ.