Fix printer speed setting

cut_paper.sh

@@ -2,4 +2,4 @@
 set -e
 dev=/dev/usb/lp0
 
-printf '\x1DVA\1' > $dev
+printf '\x1DVA\0' > $dev

print_image.sh

@@ -17,7 +17,7 @@ size_y="$(hex_size "$(echo "$data_header" | cut -d' ' -f 2)")"
 
 # Set print speed
 printf '\x1D(K\2\0' > $dev
-printf '51' > $dev
+printf '21' > $dev
 
 # Upload graphics data
 printf '\x1D(L' > $dev
@@ -34,4 +34,5 @@ printf '\x1D(L\2\0' > $dev
 printf '02' > $dev
 
 # Cut paper
-printf '\n\n\n\x1DVA\0' > $dev
+printf '\n\n\n' > $dev
+printf '\x1DVA\0' > $dev