diff --git a/build-constraints.yaml b/build-constraints.yaml
index 1155a050..51391607 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1469,6 +1469,12 @@ expected-test-failures:
     # https://github.com/afcowie/http-streams/issues/80
     - http-streams
 
+    # https://github.com/Soostone/uri-bytestring/issues/9
+    - uri-bytestring
+
+    # https://github.com/MichaelXavier/cron/issues/13
+    - cron
+
 # Haddocks which are expected to fail. Same concept as expected test failures.
 expected-haddock-failures:
     # https://github.com/acw/bytestring-progress/issues/4
diff --git a/debian-bootstrap.sh b/debian-bootstrap.sh
index de24152e..9438d78b 100755
--- a/debian-bootstrap.sh
+++ b/debian-bootstrap.sh
@@ -54,6 +54,7 @@ apt-get install -y \
     libgtk-3-dev \
     libxml2-dev \
     libgsasl7-dev \
+    libphash0-dev \
     libzmq3-dev
 
 mkdir /tmp/nettle-build