it seems that the jaguar board won't boot at all if the sdcard is inserted, even if no OS is installed on the sdcard.
I only get one LED (except power led) instead of 4 and no display output. It works well if sd card is removed.

That's interesting. I'll have to try with it out when I get home.

My Jaguarboard boots just fine with the SDcard inserted. Maybe if the SD Card is still formatted with Linux partitions or not formatted at all it may cause problems. I'm not sure as I formatted the card in FAT32 before I even installed Windows 10.

I tested on my side, no matter the SD card is in or out, Jaguarboard boots fine; No matter it is formatted or not, it boots fine.
@ric96, did you try to change a SD card? What system you installed? Can you show me the details by video?

could be a bad adapter, changed back to the one provided with the board and now it works