diff --git a/lib/index.js b/lib/index.js
index 2c99a9a..3ebb33a 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -1,6 +1,6 @@
 import * as system from './system.js';
 import { abiToNodeRange, // eslint-disable-line no-duplicate-imports
-  toFancyArch, toFancyPlatform } from './system.js';
+  hostPlatform, knownArchs, toFancyArch, toFancyPlatform } from './system.js';
 import { localPlace, remotePlace } from './places.js';
 import { log, wasReported } from './log.js';
 import build from './build.js';
@@ -54,8 +54,15 @@ export async function need ({
     if (await download(remote, downloaded)) return downloaded;
     downloadFailed = true;
   }
-  if (downloadFailed) log.info('Not found in GitHub releases. Building from source...');
-  if (forceBuild) log.info('Building base binary from source:', path.basename(built));
+  if (downloadFailed) log.info('Not found in GitHub releases');
+  log.info('Building base binary from source:', path.basename(built));
+  if (hostPlatform !== platform) {
+    throw wasReported(`Not able to build for '${platform}' here, only for '${hostPlatform}'`);
+  }
+  if (knownArchs.indexOf(arch) < 0) {
+    throw wasReported(`Unknown arch '${arch}'. Specify ${knownArchs.join(', ')}`);
+  }
+
   await build(nodeVersion, arch, built);
   return built;
 }