diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index e1fb22ca..c50ff6c2 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -81,9 +81,9 @@ jobs:
       run: |
         make aw-server-rust
 
-    - name: Check that jniLibs present
+    - name: Check that jniLibs present and valid ELF
       run: |
-        test -e mobile/src/main/jniLibs/x86_64/libaw_server.so
+        python3 scripts/check-jnilibs.py
 
     - name: Upload jniLibs artifact
       uses: actions/upload-artifact@v4
@@ -205,9 +205,9 @@ jobs:
         key: ${{ env.cache-name }}-release-${{ env.RELEASE }}-ndk-${{ env.NDK_VERSION }}-${{ hashFiles('.git/modules/aw-server-rust/HEAD') }}
         fail-on-cache-miss: false
 
-    - name: Check that jniLibs present
+    - name: Check that jniLibs present and valid ELF
       run: |
-        test -e mobile/src/main/jniLibs/x86_64/libaw_server.so
+        python3 scripts/check-jnilibs.py
 
     - name: Verify versionName matches tag
       if: startsWith(github.ref, 'refs/tags/v')  # only on runs triggered from tag
@@ -289,9 +289,9 @@ jobs:
         name: jniLibs
         path: mobile/src/main/jniLibs/
 
-    - name: Check that jniLibs present
+    - name: Check that jniLibs present and valid ELF
       run: |
-        test -e mobile/src/main/jniLibs/x86_64/libaw_server.so
+        python3 scripts/check-jnilibs.py
 
     # Test
     - name: Test
diff --git a/mobile/build.gradle b/mobile/build.gradle
index 619fa488..d3d82822 100644
--- a/mobile/build.gradle
+++ b/mobile/build.gradle
@@ -38,6 +38,13 @@ android {
             applicationIdSuffix ".debug"
             jniDebuggable true
             renderscriptDebuggable true
+            // Limit debug APK to modern ABIs used by CI emulators and physical devices.
+            // armeabi-v7a debug Rust binaries are very large and can corrupt the CI
+            // artifact when disk space is tight; they aren't needed for x86_64 emulator
+            // runs or any arm64-v8a device released since ~2014.
+            ndk {
+                abiFilters 'arm64-v8a', 'x86_64'
+            }
         }
     }
     compileOptions {
diff --git a/scripts/check-jnilibs.py b/scripts/check-jnilibs.py
new file mode 100755
index 00000000..3f349ddf
--- /dev/null
+++ b/scripts/check-jnilibs.py
@@ -0,0 +1,62 @@
+#!/usr/bin/env python3
+import os
+import struct
+import sys
+
+
+ABIS = ["arm64-v8a", "armeabi-v7a", "x86", "x86_64"]
+LIB_NAME = "libaw_server.so"
+
+
+def check_lib(abi):
+    path = os.path.join("mobile", "src", "main", "jniLibs", abi, LIB_NAME)
+    if not os.path.exists(path):
+        print(f"MISSING  {path}", file=sys.stderr)
+        return False
+
+    fsize = os.path.getsize(path)
+    with open(path, "rb") as f:
+        header = f.read(64)
+
+    if header[:4] != b"\x7fELF":
+        print(f"NOT_ELF  {path}", file=sys.stderr)
+        return False
+
+    if len(header) < 64:
+        print(
+            f"CORRUPT  {path}: file too small for ELF header "
+            f"({len(header)} bytes)",
+            file=sys.stderr,
+        )
+        return False
+
+    e_class = header[4]  # 1=32-bit, 2=64-bit
+    if e_class == 1:
+        e_shoff = struct.unpack("<I", header[32:36])[0]
+    elif e_class == 2:
+        e_shoff = struct.unpack("<Q", header[40:48])[0]
+    else:
+        print(f"CORRUPT  {path}: unknown ELF class {e_class}", file=sys.stderr)
+        return False
+
+    if e_shoff != 0 and e_shoff >= fsize:
+        print(
+            f"CORRUPT  {path}: section header past EOF "
+            f"(e_shoff=0x{e_shoff:x}, size={fsize})",
+            file=sys.stderr,
+        )
+        return False
+
+    print(f"OK       {abi}/{LIB_NAME}  ({fsize:,} bytes)")
+    return True
+
+
+def main():
+    ok = True
+    for abi in ABIS:
+        ok = check_lib(abi) and ok
+    return 0 if ok else 1
+
+
+if __name__ == "__main__":
+    sys.exit(main())