diff --git a/.github/workflows/multiarch_checks.yml b/.github/workflows/multiarch_checks.yml
index bbbde610b5e..dd2c70d88a8 100644
--- a/.github/workflows/multiarch_checks.yml
+++ b/.github/workflows/multiarch_checks.yml
@@ -22,7 +22,7 @@ concurrency:
 
 jobs:
   multiarch-prim-rev:
-    name: ${{ matrix.config.platform }} - ${{ matrix.config.batch }}
+    name: ${{ matrix.config.platform }} ${{ matrix.config.batch }}
     runs-on: ubuntu-latest
 
     strategy:
@@ -44,6 +44,11 @@ jobs:
           - { platform: arm/v6, batch: 12}
           - { platform: arm/v6, batch: 13}
           - { platform: arm/v6, batch: 14}
+          - { platform: arm/v6, batch: 15}
+          - { platform: arm/v6, batch: 16}
+          - { platform: arm/v6, batch: 17}
+          - { platform: arm/v6, batch: 18}
+          - { platform: arm/v6, batch: 19}
 
     steps:
       - uses: actions/checkout@v3
@@ -57,15 +62,15 @@ jobs:
             cd /work
             PrimTests=(test/unit/math/prim/prob/*.cpp test/unit/math/prim/core/*.cpp test/unit/math/prim/meta/*.cpp test/unit/math/prim/err/*.cpp test/unit/math/prim/functor/*.cpp)
             NTests=${#PrimTests[@]}
-            TestsPerBatch="$(($NTests / 15))"
+            TestsPerBatch="$(($NTests / 20))"
             StartOfBatch="$((${{ matrix.config.batch }} * $TestsPerBatch))"
             # Compile and run in sub-batches of 5 to fail faster
             echo "${PrimTests[@]:${StartOfBatch}:${TestsPerBatch}}" | xargs -n 5 python ./runTests.py -j2
           shell: bash
 
-    - name: Upload gtest_output xml
-      uses: actions/upload-artifact@v3
-      if: failure()
-      with:
-        name: gtest_outputs_xml
-        path: '**/*_test.xml'
+      - name: Upload gtest_output xml
+        uses: actions/upload-artifact@v3
+        if: failure()
+        with:
+          name: gtest_outputs_xml
+          path: '**/*_test.xml'