# This change sets the bootdelay to 2 seconds.  On old devices
# the bootdelay may be in the environment variable partitions.
# When updating a system, u-boot setenv command must be used
# to set the bootdelay to 2 in the environment.  A bootdelay
# of zero will make it nearly impossible to enter U-Boot,
# and zero is the old default, and may be in the environment.
# For MTCDT only the unpowered EXAR serial to USB convertor
# leaks the output of the console back to the input in some
# cases.  Therefore it is necessary to flush the UART before
# attempting to monitor keystrokes.  The output of the
# console must be quiet, or in the case of the normal
# boot where the EXAR part is unpowered, the read of the
# keyboard may be reading output to the console screen.
# This problem never occurs if the EXAR part is connected
# to a PC, and is powered.
diff -Naru orig/common/autoboot.c new/common/autoboot.c
--- orig/common/autoboot.c	2019-08-15 10:56:58.183468370 -0500
+++ new/common/autoboot.c	2019-08-15 10:30:11.363515940 -0500
@@ -219,6 +219,12 @@
 	printf("Hit any key to stop autoboot: %2d ", bootdelay);
 #endif
 
+        /* Flush input -- must be done because of loopback
+         * issue on MTCDT models with unpowered EXAR part
+         * which do loopback unintentionally by default.
+         */
+        while (tstc())
+                getc();
 	/*
 	 * Check if key already pressed
 	 */
diff -Naru orig/configs/at91sam9x5ek_nandflash_defconfig new/configs/at91sam9x5ek_nandflash_defconfig
--- orig/configs/at91sam9x5ek_nandflash_defconfig	2019-08-15 10:49:30.223481632 -0500
+++ new/configs/at91sam9x5ek_nandflash_defconfig	2019-08-15 10:50:10.703480433 -0500
@@ -3,7 +3,7 @@
 CONFIG_TARGET_AT91SAM9X5EK=y
 CONFIG_SPL=n
 CONFIG_SYS_EXTRA_OPTIONS="AT91SAM9X5,SYS_USE_NANDFLASH"
-CONFIG_BOOTDELAY=0
+CONFIG_BOOTDELAY=2
 CONFIG_HUSH_PARSER=y
 CONFIG_SYS_PROMPT="U-Boot> "
 CONFIG_CMD_BOOTZ=y