修改/home/data/AR9344/SDK/sdk/boot/u-boot/common/main.c文件

 #ifdef CONFIG_MENUPROMPT
     printf(CONFIG_MENUPROMPT, bootdelay);
 #else
     printf("Hit any key to stop autoboot: %2d ", bootdelay);
 #endif
 
 #if defined CONFIG_ZERO_BOOTDELAY_CHECK
     /*
      * Check if key already pressed
      * Don't check if bootdelay < 0
      */
     if (bootdelay >= 0) {
         if (tstc()) {   /* we got a key press   */
             (void) getc();  /* consume input    */
             puts ("\b\b\b 0");
             abort = 1;  /* don't auto boot  */
         }
     }
 #endif
 
     while ((bootdelay > 0) && (!abort)) {
         int i;
 
         --bootdelay;
         /* delay 100 * 10ms */
         for (i=0; !abort && i<100; ++i) {
             if (tstc()) {   /* we got a key press   */
                 if(13 == getc()){
                     abort  = 1; /* don't auto boot  */
                     bootdelay = 0;  /* no more delay    */
 # ifdef CONFIG_MENUKEY
                     menukey = getc();
 # else
                     (void) getc();  /* consume input    */
 # endif
                     break;
                 }
             }
             udelay (10000);
         }
 
         printf ("\b\b\b%2d ", bootdelay);
     }
 
     putc ('\n');

回车键：VK_RETURN (13)

修改之后，只有按下回车键，才会进入u-boot