zynq_image: fix image size for qemu

zynq_image.nix

@@ -22,9 +22,10 @@ in {
       set -x
       base=$(dirname $0)
 
-      cp $base/root.squashfs /tmp/
-      chmod +w /tmp/root.squashfs
-      truncate -s 64m /tmp/root.squashfs
+      mkdir ./tmp/
+      cp $base/root.squashfs ./tmp/
+      chmod +w ./tmp/root.squashfs
+      truncate -s 64M ./tmp/root.squashfs
 
       qemu-system-arm \
         -M xilinx-zynq-a9 \
@@ -34,7 +35,7 @@ in {
         -dtb $base/zynq-zc702.dtb \
         -kernel $base/zImage \
         -initrd $base/initrd \
-        -drive file=/tmp/root.squashfs,if=sd,format=raw \
+        -drive file=./tmp/root.squashfs,if=sd,format=raw \
         -append "${cmdline}"
     '';
   in pkgs.runCommand "zynq_image" {