diff --git a/solo-builder/builder.sh b/solo-builder/builder.sh
index 0682532..38c0831 100755
--- a/solo-builder/builder.sh
+++ b/solo-builder/builder.sh
@@ -1,6 +1,6 @@
 #!/bin/bash
 
-# USAGE: builder.sh -a GIT_ACCOUNT -r GIT_REPO -b GIT_BRANCH
+# USAGE: builder.sh -a GIT_ACCOUNT -r GIT_REPO -b GIT_BRANCH -b BUILD_MACHINE
     
 # EXAMPLE: builder.sh -a OpenSolo -r 3dr-arm-yocto-bsp -b Master
 #   These are also the defaults that will be used if options are not specified
@@ -12,15 +12,24 @@
 GIT_ACCOUNT=OpenSolo
 GIT_REPO=3dr-arm-yocto-bsp
 GIT_BRANCH=master
+BUILD_MACHINE=both
+
+# Check if the build directory is there. If not, setup steps were skipped or messed up.
+if [ ! -d "/solo-build" ]; then
+  echo "No build directory. Did you skip all the other steps?"
+  exit 1
+fi
+
 
 # Check command line options for git account, repo, and branch.
-while getopts a:r:b: option
+while getopts a:r:b:m: option
 do
  case ${option}
  in
  a) GIT_ACCOUNT=${OPTARG};;
  r) GIT_REPO=${OPTARG};;
  b) GIT_BRANCH=${OPTARG};;
+ m) BUILD_MACHINE=$${OPTARG};;
  esac
 done
 
@@ -41,40 +50,74 @@ echo
 #Do it.
 cd /solo-build
 repo init -u https://github.com/$GIT_ACCOUNT/$GIT_REPO.git -b $GIT_BRANCH
-repo sync
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
+
+repo sync --force-sync
+
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
 
 export MACHINE=imx6solo-3dr-1080p
 EULA=1 source ./setup-environment build
 
-# -k means continue-after-error-for-as-much-as-possible
-MACHINE=imx6solo-3dr-1080p bitbake 3dr-solo -k
-MACHINE=imx6solo-3dr-artoo bitbake 3dr-controller -k
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
 
-# other options/examples, how to build just one bit, such as the pixhawk firmware from OpenSolo/meta-3dr/recipes-firmware/pixhawk/pixhawk-firmware_1.3.1.bb :
-# assuming you've run the 'export MACHINE...' and 'source ./setup...' commands first, and are in /solo-build/build/ folder as a result:
+#TIP: how to build just one bit, such as the pixhawk firmware from OpenSolo/meta-3dr/recipes-firmware/pixhawk/pixhawk-firmware_1.3.1.bb :
+#assuming you've run the 'export MACHINE...' and 'source ./setup...' commands first, and are in /solo-build/build/ folder as a result:
 #bitbake -c clean pixhawk-firmware
 #bitbake pixhawk-firmware
 #or verbose:
 #bitbake pixhawk-firmware -v
+#TIP: -k means continue-after-error-for-as-much-as-possible
 
+MACHINE=imx6solo-3dr-1080p bitbake 3dr-solo -c clean -f -k
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
 
+MACHINE=imx6solo-3dr-artoo bitbake 3dr-controller -c clean -f -k
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
+
+MACHINE=imx6solo-3dr-1080p bitbake 3dr-solo
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
+
+MACHINE=imx6solo-3dr-artoo bitbake 3dr-controller
+if [ ! $? -eq 0 ]
+then
+    exit 1
+fi
+
+#TIPS:
 # Copy the relevant files to a date/time stamped completed directory in the git repo folder for easy access (on git ignore list).
 # Make an MD5sum of each as is required for the Solo and Controller to accept the files.
-# The tar.gz and the MD5 go directly in the /log/updates/ directory on the solo and/or controller.
+# The tar.gz and the .md5 go directly in the /log/updates/ directory on the solo and/or controller.
 NEW_DIR=/vagrant/"completed_$(date +%F_%H-%M)"
 mkdir -p $NEW_DIR
-cp /solo-build/build/tmp-eglibc/deploy/images/imx6solo-3dr-1080p/3dr-solo.tar.gz $NEW_DIR
-cp /solo-build/build/tmp-eglibc/deploy/images/imx6solo-3dr-artoo/3dr-controller.tar.gz $NEW_DIR
 cd $NEW_DIR
+
+cp /solo-build/build/tmp-eglibc/deploy/images/imx6solo-3dr-1080p/3dr-solo.tar.gz $NEW_DIR
 md5sum 3dr-solo.tar.gz > 3dr-solo.tar.gz.md5
+
+cp /solo-build/build/tmp-eglibc/deploy/images/imx6solo-3dr-artoo/3dr-controller.tar.gz $NEW_DIR
 md5sum 3dr-controller.tar.gz > 3dr-controller.tar.gz.md5
 
-echo
-echo "*****************************"
-echo "Completed tar.gz and md5 checksum files for Solo and/or Controller are in a date-time stamped directory in your github directory."
 ls -lh $NEW_DIR
 
-echo
 echo
 echo "All build files located in below directories of the Vagrant virtual machine (squashfs, uImage, kernel, u-boot, dtb file, initramfs, rootfs.cpio, etc)"
 echo /solo-build/build/tmp-eglibc/deploy/images/imx6solo-3dr-1080p/