Fix boot (#459)

* Fix permission check

* Remove fails on copy

* Disable FB_BCM2708

* Don't touch the memory map from first stage

* bootcode.bin is not needed on rpi4

scripts/entry.sh

@@ -7,7 +7,7 @@ USER="root"
 dockerd -s vfs &> /dev/null &
 
 # Setup local user
-if [ "${BUILDER_UID:0}" -ne 0 ] && [ "${BUILDER_GID:0}" -ne 0 ]; then
+if [ "${BUILDER_UID:-0}" -ne 0 ] && [ "${BUILDER_GID:-0}" -ne 0 ]; then
   groupadd -g "${BUILDER_GID}" builder
   useradd -m -u "${BUILDER_UID}" -g "${BUILDER_GID}" -G docker,sudo builder
   echo "builder ALL=(ALL:ALL) NOPASSWD: ALL" >> /etc/sudoers