diff --git a/.ci/install.sh b/.ci/install.sh
index e199c73a4..5f30d27b2 100755
--- a/.ci/install.sh
+++ b/.ci/install.sh
@@ -13,7 +13,7 @@ ls
 # if [ "$(git status --ignore-submodules=dirty --porcelain)" ]; then
 # "--ignore-submodules=dirty", removed temporarily, as it did not notice as
 # expected that base was updated and kept using old cached base
-if [ "$(git status --porcelain)" ]; then
+if [ "$(git status --ignore-submodules=dirty --porcelain)" ]; then
     # what changed?
     git status
     # purge and reinit submodules
diff --git a/.circleci/config.yml b/.circleci/config.yml
index c6573922c..e81ff338f 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -11,10 +11,16 @@ jobs:
       - checkout
       - restore_cache:
           keys:
-            - deps
-            - build
+            # binary dependencies require {{ arch }} because there are different CPUs in use on the servers
+            - deps-{{ arch }}-{{ checksum ".ci/install.sh" }}
+      # need to init some stuff first or git will complain when sticking in base cache
+      - run: git submodule init base && git submodule update base && pushd base && git submodule init && git submodule update && popd
+      # we can't use command output directly for cache check so we write it to git-rev-base
+      - run: pushd base && git_rev_base=$(git describe HEAD) && popd && echo $git_rev_base && echo $git_rev_base >git-rev-base
+      - restore_cache:
+          keys:
+            - build-{{ arch }}-{{ checksum "git-rev-base" }}
       - run: echo 'export PATH=${HOME}/bin:${PATH}' >> $BASH_ENV
-
       - run:
           name: setup
           command: .ci/before_install.sh
@@ -41,12 +47,12 @@ jobs:
           name: clean up cache
           command: rm -frv ./base/build/*/{spec,cache/*}
       - save_cache:
-          key: build
+          key: build-{{ arch }}-{{ checksum "git-rev-base" }}
           paths:
             - "/home/ko/.ccache"
             - "base"
       - save_cache:
-          key: deps
+          key: deps-{{ arch }}-{{ checksum ".ci/install.sh" }}
           paths:
             - "/home/ko/bin"
             - "/home/ko/.luarocks"
diff --git a/.gitignore b/.gitignore
index ca04702a2..93abb1704 100644
--- a/.gitignore
+++ b/.gitignore
@@ -17,6 +17,7 @@ install/
 spec/unit/data
 doc/html
 git-rev
+git-rev-base
 emu
 luacov.stats.out
 trace-out.txt
diff --git a/base b/base
index 2148066d5..a7b3508f9 160000
--- a/base
+++ b/base
@@ -1 +1 @@
-Subproject commit 2148066d59205f09d60f0bbaad256526b4b309d7
+Subproject commit a7b3508f9ffefe062db78a4797119041e24058c3