fix: pd-mapper can't read zstd firmware files

nixos unstable and 24.05 switched to zstd compression for firmware
files. Roll back to the previous setup of creating a package of the
qcom firmware uncompressed, and patching pd-mapper.

closes #14

packages/default.nix

@@ -27,4 +27,6 @@ rec {
   qrtr = pkgs.callPackage ./qrtr { };
 
   "x13s/extra-firmware" = pkgs.callPackage ./extra-firmware.nix { };
+
+  uncompressed-firmware = pkgs.callPackage ./uncompressed-firmware.nix { };
 }

packages/pd-mapper/pd-mapper-firmware-path.diff

@@ -4,10 +4,10 @@ index 65c4b80..669d9a0 100644
 +++ b/pd-mapper.c
 @@ -194,7 +194,7 @@ static int pd_load_map(const char *file)
  }
- 
+
  #ifndef ANDROID
 -#define FIRMWARE_BASE	"/lib/firmware/"
-+#define FIRMWARE_BASE	"/run/current-system/firmware/"
++#define FIRMWARE_BASE	"/run/current-system/sw/share/uncompressed-firmware/"
  #else
  #define FIRMWARE_BASE	"/vendor/firmware/"
  #endif

packages/uncompressed-firmware.nix

@@ -0,0 +1,24 @@
+{
+  runCommand,
+  buildEnv,
+  firmwareFilesList ? [ ],
+}:
+runCommand "qcom-modem-uncompressed-firmware-share"
+  {
+    firmwareFiles = buildEnv {
+      name = "qcom-modem-uncompressed-firmware";
+      paths = firmwareFilesList;
+      pathsToLink = [
+        "/lib/firmware/rmtfs"
+        "/lib/firmware/qcom"
+      ];
+    };
+  }
+  ''
+    PS4=" $ "
+    (
+    set -x
+    mkdir -p $out/share/
+    ln -s $firmwareFiles/lib/firmware/ $out/share/uncompressed-firmware
+    )
+  ''