diff --git a/.vscode/settings.json b/.vscode/settings.json
index dff35f935..54243280d 100644
--- a/.vscode/settings.json
+++ b/.vscode/settings.json
@@ -8,7 +8,7 @@
     "**/build": true
   },
   "editor.codeActionsOnSave": {
-    "source.fixAll.eslint": true
+    "source.fixAll.eslint": "explicit"
   },
   "flow.useNPMPackagedFlow": true,
   "javascript.validate.enable": false,
diff --git a/packages/cli-config/src/__tests__/index-test.ts b/packages/cli-config/src/__tests__/index-test.ts
index c11f6e877..3740e8d1c 100644
--- a/packages/cli-config/src/__tests__/index-test.ts
+++ b/packages/cli-config/src/__tests__/index-test.ts
@@ -24,12 +24,10 @@ const REACT_NATIVE_MOCK = {
     module.exports = {
       platforms: {
         ios: {
-          linkConfig: ios.linkConfig,
           projectConfig: ios.projectConfig,
           dependencyConfig: ios.dependencyConfig,
         },
         android: {
-          linkConfig: android.linkConfig,
           projectConfig: android.projectConfig,
           dependencyConfig: android.dependencyConfig,
         },
@@ -38,6 +36,21 @@ const REACT_NATIVE_MOCK = {
   `,
 };
 
+const PLATFORM_MOCK = {
+  'node_modules/react-native-os/package.json': '{}',
+  'node_modules/react-native-os/react-native.config.js': `
+    const os = require("${iosPath}");
+    module.exports = {
+      platforms: {
+        os: {
+          projectConfig: os.projectConfig,
+          dependencyConfig: os.dependencyConfig,
+        },
+      },
+    };
+  `,
+};
+
 // Removes string from all key/values within an object
 const removeString = (config, str) =>
   JSON.parse(
@@ -373,6 +386,70 @@ test('should apply build types from dependency config', async () => {
   ).toMatchSnapshot();
 });
 
+test('should be able to read multiple platforms from many packages', async () => {
+  DIR = getTempDirectory('config_test_apply_dependency_config');
+  writeFiles(DIR, {
+    ...REACT_NATIVE_MOCK,
+    ...PLATFORM_MOCK,
+    'package.json': `{
+      "dependencies": {
+        "react-native": "0.0.1",
+        "react-native-os": "0.0.1"
+      }
+    }`,
+  });
+  const {platforms} = await loadConfigAsync({projectRoot: DIR});
+  expect(removeString(platforms, DIR)).toMatchInlineSnapshot(`
+    Object {
+      "android": Object {},
+      "ios": Object {},
+      "os": Object {},
+    }
+  `);
+});
+
+test('should be able to read only selected platform', async () => {
+  DIR = getTempDirectory('config_test_apply_dependency_config');
+  writeFiles(DIR, {
+    ...REACT_NATIVE_MOCK,
+    ...PLATFORM_MOCK,
+    'package.json': `{
+      "dependencies": {
+        "react-native": "0.0.1",
+        "react-native-os": "0.0.1"
+      }
+    }`,
+  });
+  const {platforms} = await loadConfigAsync({
+    projectRoot: DIR,
+    selectedPlatform: 'os',
+  });
+  expect(removeString(platforms, DIR)).toMatchInlineSnapshot(`
+    Object {
+      "os": Object {},
+    }
+  `);
+});
+
+test('should be able to read no platforms when non-existent selected', async () => {
+  DIR = getTempDirectory('config_test_apply_dependency_config');
+  writeFiles(DIR, {
+    ...REACT_NATIVE_MOCK,
+    ...PLATFORM_MOCK,
+    'package.json': `{
+      "dependencies": {
+        "react-native": "0.0.1",
+        "react-native-os": "0.0.1"
+      }
+    }`,
+  });
+  const {platforms} = await loadConfigAsync({
+    projectRoot: DIR,
+    selectedPlatform: 'macos',
+  });
+  expect(removeString(platforms, DIR)).toMatchInlineSnapshot(`Object {}`);
+});
+
 test('supports dependencies from user configuration with custom build type', async () => {
   DIR = getTempDirectory('config_test_apply_custom_build_config');
   writeFiles(DIR, {
diff --git a/packages/cli-config/src/loadConfig.ts b/packages/cli-config/src/loadConfig.ts
index 9ebc71ee6..b01c2d03b 100644
--- a/packages/cli-config/src/loadConfig.ts
+++ b/packages/cli-config/src/loadConfig.ts
@@ -167,7 +167,9 @@ export default function loadConfig({
           ...acc.platforms,
           ...(selectedPlatform && config.platforms[selectedPlatform]
             ? {[selectedPlatform]: config.platforms[selectedPlatform]}
-            : config.platforms),
+            : !selectedPlatform
+            ? config.platforms
+            : undefined),
         },
         healthChecks: [...acc.healthChecks, ...config.healthChecks],
       }) as Config;
@@ -267,7 +269,9 @@ export async function loadConfigAsync({
           ...acc.platforms,
           ...(selectedPlatform && config.platforms[selectedPlatform]
             ? {[selectedPlatform]: config.platforms[selectedPlatform]}
-            : config.platforms),
+            : !selectedPlatform
+            ? config.platforms
+            : undefined),
         },
         healthChecks: [...acc.healthChecks, ...config.healthChecks],
       }) as Config;