Improve build+flash script ergonomics

harrogate/flash.sh

@@ -2,6 +2,8 @@
 
 set -e
 
+cd "$(dirname "$0")"
+
 cargo build --release --features $1
 
 APPLET=harrogate
@@ -11,12 +13,12 @@ test -e "$TARGET_BIN" || {
     exit 1
 }
 
-arm-none-eabi-objcopy -O binary "$TARGET_BIN" flash.bin
-uf2conv-rs flash.bin -o flash.uf2
+arm-none-eabi-objcopy -O binary "$TARGET_BIN" image.bin
+uf2conv-rs image.bin -o image.uf2
 
 sudo mount LABEL=ITSYBOOT mnt/
 echo "Flashing..."
-sudo cp flash.uf2 mnt/flash.uf2
+sudo cp image.uf2 mnt/image.uf2
 sync
 echo "Done."
 sudo umount mnt/