Backs up old sd card on copy.

flake.nix

@@ -24,19 +24,20 @@
       uncompressed = import ./sd-card.nix { inherit pkgs crossPkgs; compress = false; };
 
       vmscript = pkgs.writeScriptBin "vmscript" ''
-      #!${pkgs.runtimeShell}
-      img=./sd-card.img
-      cp ${self.outputs.packages.${system}.uncompressed}/sd-card.img $img
-      chmod 640 $img
-      ${pkgs.qemu}/bin/qemu-system-aarch64 \
-        -machine raspi3b \
-        -kernel "${crossPkgs.ubootRaspberryPi3_64bit}/u-boot.bin" \
-        -cpu max \
-        -m 1G \
-        -smp 4 \
-        -drive file="$img",format=raw \
-        -serial null \
-        -serial mon:stdio
+        #!${pkgs.runtimeShell} -e
+        img=./sd-card.img
+        cp -b ${self.outputs.packages.${system}.uncompressed}/sd-card.img $img
+        chmod 640 $img
+        ${pkgs.qemu}/bin/qemu-system-aarch64 \
+          -machine raspi3b \
+          -kernel "${crossPkgs.ubootRaspberryPi3_64bit}/u-boot.bin" \
+          -cpu max \
+          -m 1G \
+          -smp 4 \
+          -drive file="$img",format=raw \
+          -nographic \
+          -serial null \
+          -serial mon:stdio
       '';
 
     };