Fix typo in the doc

Bug: N/A
Test: N/A
Change-Id: I6a9ede6f189116aa5d5c22167b5e9e0d5762606c
diff --git a/docs/getting_started/index.md b/docs/getting_started/index.md
index ac5d38b..f598034 100644
--- a/docs/getting_started/index.md
+++ b/docs/getting_started/index.md
@@ -90,7 +90,7 @@
 
 ```shell
 banchan com.android.virt aosp_arm64   // or aosp_x86_64 if the device is cuttlefish
-m apps_only dist
+UNBUNDLED_BUILD_SDKS_FROM_SOURCE=true m apps_only dist
 adb install out/dist/com.android.virt.apex
 adb reboot
 ```
diff --git a/microdroid/README.md b/microdroid/README.md
index 783f300..a652139 100644
--- a/microdroid/README.md
+++ b/microdroid/README.md
@@ -31,7 +31,7 @@
 
 ```sh
 banchan com.android.virt aosp_arm64
-UNBUNDLED_BUILD_SDKS_FROM_SOURCES=true m apps_only dist
+UNBUNDLED_BUILD_SDKS_FROM_SOURCE=true m apps_only dist
 adb install out/dist/com.android.virt.apex
 adb reboot
 ```