avionic design with actual uboot and tooling

submodule of avionic design uboot bootloader and with included tools to
get you started , read readme.md and readme-tk1-loader.md

u-boot/tools/env/Makefile

@@ -0,0 +1,38 @@
+#
+# (C) Copyright 2002-2006
+# Wolfgang Denk, DENX Software Engineering, wd@denx.de.
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+# fw_printenv is supposed to run on the target system, which means it should be
+# built with cross tools. Although it may look weird, we only replace "HOSTCC"
+# with "CC" here for the maximum code reuse of scripts/Makefile.host.
+HOSTCC = $(CC)
+
+# Compile for a hosted environment on the target
+HOST_EXTRACFLAGS  = $(patsubst -I%,-idirafter%, $(filter -I%, $(UBOOTINCLUDE))) \
+		-idirafter $(srctree)/tools/env \
+		-DUSE_HOSTCC \
+		-DTEXT_BASE=$(TEXT_BASE)
+
+ifeq ($(MTD_VERSION),old)
+HOST_EXTRACFLAGS += -DMTD_OLD
+endif
+
+always := fw_printenv
+hostprogs-y := fw_printenv
+
+lib-y += fw_env.o \
+	crc32.o ctype.o linux_string.o \
+	env_attr.o env_flags.o aes.o
+
+fw_printenv-objs := fw_env_main.o $(lib-y)
+
+quiet_cmd_crosstools_strip = STRIP   $^
+      cmd_crosstools_strip = $(STRIP) $^; touch $@
+
+$(obj)/.strip: $(obj)/fw_printenv
+	$(call cmd,crosstools_strip)
+
+always += .strip