diff --git a/pkgs/applications/editors/vscode/extensions/default.nix b/pkgs/applications/editors/vscode/extensions/default.nix
index 6ab87df26539..4ada6b024fe3 100644
--- a/pkgs/applications/editors/vscode/extensions/default.nix
+++ b/pkgs/applications/editors/vscode/extensions/default.nix
@@ -1115,7 +1115,7 @@ let
             publisher = "Continue";
             version = "1.1.49";
           }
-          // sources.${stdenv.system};
+          // sources.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}");
         nativeBuildInputs = lib.optionals stdenv.hostPlatform.isLinux [ autoPatchelfHook ];
         buildInputs = [ (lib.getLib stdenv.cc.cc) ];
         meta = {
@@ -1387,7 +1387,7 @@ let
             publisher = "devsense";
             version = "1.41.14332";
           }
-          // sources.${stdenv.system};
+          // sources.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}");
 
         nativeBuildInputs = [ autoPatchelfHook ];
 
@@ -3334,7 +3334,7 @@ let
             publisher = "ms-dotnettools";
             version = "2.2.3";
           }
-          // sources.${stdenv.system};
+          // sources.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}");
         nativeBuildInputs = lib.optionals stdenv.hostPlatform.isLinux [ autoPatchelfHook ];
         buildInputs = [
           (lib.getLib stdenv.cc.cc)
diff --git a/pkgs/by-name/bu/bulloak/package.nix b/pkgs/by-name/bu/bulloak/package.nix
index 069374c134b3..976a622d397c 100644
--- a/pkgs/by-name/bu/bulloak/package.nix
+++ b/pkgs/by-name/bu/bulloak/package.nix
@@ -47,7 +47,9 @@ rustPlatform.buildRustPackage rec {
   doCheck = false;
 
   # provide the list of solc versions to the `svm-rs-builds` dependency
-  SVM_RELEASES_LIST_JSON = solc-versions.${stdenv.hostPlatform.system};
+  SVM_RELEASES_LIST_JSON =
+    solc-versions.${stdenv.hostPlatform.system}
+      or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
 
   meta = {
     description = "Solidity test generator based on the Branching Tree Technique";
diff --git a/pkgs/by-name/da/daytona-bin/package.nix b/pkgs/by-name/da/daytona-bin/package.nix
index bf26c54e94ea..d04b4f972fe9 100644
--- a/pkgs/by-name/da/daytona-bin/package.nix
+++ b/pkgs/by-name/da/daytona-bin/package.nix
@@ -30,7 +30,10 @@ stdenvNoCC.mkDerivation (finalAttrs: {
         };
       };
     in
-    fetchurl urls."${stdenvNoCC.hostPlatform.system}";
+    fetchurl (
+      urls."${stdenvNoCC.hostPlatform.system}"
+        or (throw "Unsupported system: ${stdenvNoCC.hostPlatform.system}")
+    );
 
   dontUnpack = true;
 
diff --git a/pkgs/by-name/no/notion-app/package.nix b/pkgs/by-name/no/notion-app/package.nix
index bd33b998b55c..05f9d46c7683 100644
--- a/pkgs/by-name/no/notion-app/package.nix
+++ b/pkgs/by-name/no/notion-app/package.nix
@@ -5,7 +5,9 @@
   unzip,
 }:
 let
-  info = (lib.importJSON ./info.json)."${stdenvNoCC.hostPlatform.parsed.cpu.name}-darwin";
+  info =
+    (lib.importJSON ./info.json)."${stdenvNoCC.hostPlatform.parsed.cpu.name}-darwin"
+      or (throw "Unsupported CPU architecture: ${stdenvNoCC.hostPlatform.parsed.cpu.name}");
 in
 stdenvNoCC.mkDerivation (finalAttrs: {
   pname = "notion-app";
diff --git a/pkgs/by-name/wk/wkhtmltopdf/package.nix b/pkgs/by-name/wk/wkhtmltopdf/package.nix
index 67c5d26ef8ef..24ecddd3dc9a 100644
--- a/pkgs/by-name/wk/wkhtmltopdf/package.nix
+++ b/pkgs/by-name/wk/wkhtmltopdf/package.nix
@@ -124,5 +124,7 @@ stdenv.mkDerivation (
     };
   }
   // lib.optionalAttrs (stdenv.hostPlatform.isDarwin) darwinAttrs
-  // lib.optionalAttrs (stdenv.hostPlatform.isLinux) linuxAttrs.${stdenv.system}
+  //
+    lib.optionalAttrs (stdenv.hostPlatform.isLinux)
+      linuxAttrs.${stdenv.system} or (throw "Unsupported system: ${stdenv.system}")
 )
diff --git a/pkgs/by-name/ze/zenn-cli/package.nix b/pkgs/by-name/ze/zenn-cli/package.nix
index eac27008ec60..380b4cc8fc9b 100644
--- a/pkgs/by-name/ze/zenn-cli/package.nix
+++ b/pkgs/by-name/ze/zenn-cli/package.nix
@@ -24,7 +24,9 @@ let
   go-turbo = stdenv.mkDerivation {
     pname = "go-turbo";
     version = go-turbo-version;
-    src = go-turbo-srcs.${stdenv.hostPlatform.system};
+    src =
+      go-turbo-srcs.${stdenv.hostPlatform.system}
+        or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
     nativeBuildInputs = [ autoPatchelfHook ];
     dontBuild = true;
     installPhase = ''
diff --git a/pkgs/development/compilers/swift/compiler/default.nix b/pkgs/development/compilers/swift/compiler/default.nix
index c23b8e0877f5..993ca970c06e 100644
--- a/pkgs/development/compilers/swift/compiler/default.nix
+++ b/pkgs/development/compilers/swift/compiler/default.nix
@@ -484,6 +484,7 @@ stdenv.mkDerivation {
             "aarch64" = "AArch64";
           }
           .${targetPlatform.parsed.cpu.name}
+            or (throw "Unsupported CPU architecture: ${targetPlatform.parsed.cpu.name}")
         }
       "
       buildProject llvm llvm-project/llvm
diff --git a/pkgs/development/python-modules/tritonclient/default.nix b/pkgs/development/python-modules/tritonclient/default.nix
index 49393e0c7671..4448047f9611 100644
--- a/pkgs/development/python-modules/tritonclient/default.nix
+++ b/pkgs/development/python-modules/tritonclient/default.nix
@@ -35,8 +35,11 @@ buildPythonPackage rec {
       inherit pname version format;
       python = "py3";
       dist = "py3";
-      platform = platforms.${stdenv.hostPlatform.system} or { };
-      sha256 = hashes.${stdenv.hostPlatform.system} or { };
+      platform =
+        platforms.${stdenv.hostPlatform.system}
+          or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
+      sha256 =
+        hashes.${stdenv.hostPlatform.system} or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
     };
 
   propagatedBuildInputs = [
diff --git a/pkgs/development/python-modules/vl-convert-python/librusty_v8.nix b/pkgs/development/python-modules/vl-convert-python/librusty_v8.nix
index 53aaf4910485..636b86d4c6e1 100644
--- a/pkgs/development/python-modules/vl-convert-python/librusty_v8.nix
+++ b/pkgs/development/python-modules/vl-convert-python/librusty_v8.nix
@@ -10,7 +10,9 @@ let
     fetchurl {
       name = "librusty_v8-${args.version}";
       url = "https://github.com/denoland/rusty_v8/releases/download/v${args.version}/librusty_v8_release_${stdenv.hostPlatform.rust.rustcTarget}.a.gz";
-      sha256 = args.shas.${stdenv.hostPlatform.system};
+      sha256 =
+        args.shas.${stdenv.hostPlatform.system}
+          or (throw "Unsupported system: ${stdenv.hostPlatform.system}");
       meta = {
         inherit (args) version;
         sourceProvenance = with lib.sourceTypes; [ binaryNativeCode ];
diff --git a/pkgs/development/rocm-modules/6/llvm/default.nix b/pkgs/development/rocm-modules/6/llvm/default.nix
index c4174805684c..cdb5d705b068 100644
--- a/pkgs/development/rocm-modules/6/llvm/default.nix
+++ b/pkgs/development/rocm-modules/6/llvm/default.nix
@@ -170,6 +170,7 @@ let
       "aarch64" = "AArch64";
     }
     .${llvmStdenv.targetPlatform.parsed.cpu.name}
+      or (throw "Unsupported CPU architecture: ${llvmStdenv.targetPlatform.parsed.cpu.name}")
   }";
   # -ffat-lto-objects = emit LTO object files that are compatible with non-LTO-supporting builds too
   # FatLTO objects are a special type of fat object file that contain LTO compatible IR in addition to generated object code,
diff --git a/pkgs/top-level/all-packages.nix b/pkgs/top-level/all-packages.nix
index 286e790df8e3..b1703ecb84fc 100644
--- a/pkgs/top-level/all-packages.nix
+++ b/pkgs/top-level/all-packages.nix
@@ -1387,6 +1387,8 @@ with pkgs;
       pkgsCross.gnu32.callPackage ../applications/emulators/box86 args
     else if stdenv.hostPlatform.isAarch64 then
       pkgsCross.armv7l-hf-multiplatform.callPackage ../applications/emulators/box86 args
+    else if stdenv.hostPlatform.isRiscV64 then
+      pkgsCross.riscv32.callPackage ../applications/emulators/box86 args
     else
       throw "Don't know 32-bit platform for cross from: ${stdenv.hostPlatform.stdenv}";