Altera cyclone5 board can't start without serial cable plugged

[Altera_Forum]

I'm using the Altera Cyclone V Soc dev Kit and Linux Angstrom provides by rocketboards (http://rocketboards.org/foswiki/documentation/gsrd141) Kernel is : 3.10 LTSI. For me, Linux can't start if any serial cable is not plugged on UART USB port (J8).  

I already removed getty which launched a login prompt at start up. I also tried to change CMD_LINE in .config kernel's file to disable console. What should I change to enable linux to start properly ? Is that simply possible ? Have I to rebuild the kernel or u-boot and change configuration ?

[Altera_Forum]

http://www.terasic.com.tw/cgi-bin/page/archive.pl?language=english&categoryno=167&no=816&partno=4 

Please check "How to Fix microSD Card Boot NG(rev. D)", hopefully it hits your question.

[Altera_Forum]

could you make a complete reset? flash a 14.1 SOF file, flash 14.1 SD card GHRD image, and ensure all teh jumper in the default form? just to isolate is not the version of the GHRD that you are using got error.

[Altera_Forum]

We had the same problem with our custom board. A floating RX pin is no good. This thread helped us to find the problem.