diff --git a/pkgs/development/python-modules/ocrmypdf/default.nix b/pkgs/development/python-modules/ocrmypdf/default.nix
index 0f2dd593c62e..5c6b87b38fed 100644
--- a/pkgs/development/python-modules/ocrmypdf/default.nix
+++ b/pkgs/development/python-modules/ocrmypdf/default.nix
@@ -34,7 +34,13 @@ buildPythonPackage rec {
     owner = "jbarlow83";
     repo = "OCRmyPDF";
     rev = "v${version}";
-    sha256 = "sha256-gFlQztrRN69HtR6sTJl8tryuTibxQrz97QcS5UkFOVs=";
+    # The content of .git_archival.txt is substituted upon tarball creation,
+    # which creates indeterminism if master no longer points to the tag.
+    # See https://github.com/jbarlow83/OCRmyPDF/issues/841
+    extraPostFetch = ''
+      rm "$out/.git_archival.txt"
+    '';
+    sha256 = "0zw7c6l9fkf128gxsbd7v4abazlxiygqys6627jpsjbmxg5jgp5w";
   };
 
   SETUPTOOLS_SCM_PRETEND_VERSION = version;
diff --git a/pkgs/development/python-modules/pikepdf/default.nix b/pkgs/development/python-modules/pikepdf/default.nix
index 027369d3d01a..7b380627d75a 100644
--- a/pkgs/development/python-modules/pikepdf/default.nix
+++ b/pkgs/development/python-modules/pikepdf/default.nix
@@ -24,12 +24,12 @@
 
 buildPythonPackage rec {
   pname = "pikepdf";
-  version = "3.1.0";
+  version = "3.1.1";
   disabled = ! isPy3k;
 
   src = fetchPypi {
     inherit pname version;
-    sha256 = "aeb813b5f36534d2bedf08487ab2b022c43f4c8a3e86e611c5f7c8fb97309db5";
+    sha256 = "sha256-klSUszWsIIz7o0/Ql8K4CWYujBH0mAbqyUcabpn1SkQ=";
   };
 
   patches = [