Add NAND issues warning to nand-sata-install

packages/bsp/common/usr/sbin/nand-sata-install

@@ -290,12 +290,31 @@ umountdevice()
 	fi
 } # umountdevice
 
+show_nand_warning()
+{
+	local temp_rc=$(mktemp)
+	cat <<-'EOF' > $temp_rc
+	screen_color = (WHITE,RED,ON)
+	EOF
+	local warn_text="You are installing the system to sunxi NAND.
+
+	This is not recommended as NAND has \Z1worse performance
+	and reliability\Zn than a good SD card.
+
+	You have been warned."
+
+	DIALOGRC=$temp_rc dialog --title "NAND warning" --backtitle "$backtitle" --colors \
+		--ok-label "I understand and agree" --msgbox "$warn_text" 10 70
+}
 
 # formatting sunxi NAND - no parameters, fixed solution.
 #
 formatnand()
 {
 	[[ ! -e /dev/nand ]] && echo "NAND error" && exit 0
+
+	show_nand_warning
+
 	dialog --title "$title" --backtitle "$backtitle" --infobox "\nFormating ... up to one minute." 5 40
 	if [[ $DEVICE_TYPE = a20 ]]; then
 		(echo y;) | sunxi-nand-part -f a20 /dev/nand 65536 'bootloader 65536' 'linux 0' >> $logfile 2>&1