diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index a08d07fe77a1f432d76851f93c5639714d32f4fd..c8995972397b0b4eee5e00b527d99897cf39050c 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -37,23 +37,19 @@ jobs:
 
     - name: "Upgrade Pip"
       run: |
-        python -m pip install --upgrade pip
+        python -m pip install -v --upgrade pip
 
     - name: "Install CI Dependencies"
       run: |
-        python -m pip install wheel coverage
-
-    - name: "Install Tahoe-LAFS master@HEAD"
-      run: |
-        python -m pip install git+https://github.com/tahoe-lafs/tahoe-lafs@master#egg=tahoe-lafs
+        python -m pip install -v wheel coverage
 
     - name: "Install Test Dependencies"
       run: |
-        python -m pip install -r test-requirements.txt
+        python -m pip install -v -r test-requirements.txt
 
     - name: "Install ZKAPAuthorizer"
       run: |
-        python -m pip install ./
+        python -m pip install -v ./
 
     - name: "Dump Python Environment"
       run: |
diff --git a/nix/setup.cfg.patch b/nix/setup.cfg.patch
new file mode 100644
index 0000000000000000000000000000000000000000..c2cdeea1617d10691e9b151d1b3b1308c451952f
--- /dev/null
+++ b/nix/setup.cfg.patch
@@ -0,0 +1,13 @@
+diff --git a/setup.cfg b/setup.cfg
+index dfc49607..822ea8dd 100644
+--- a/setup.cfg
++++ b/setup.cfg
+@@ -40,7 +40,7 @@ install_requires =
+     # incompatible with Tahoe-LAFS'.  So duplicate them here (the ones that
+     # have been observed to cause problems).
+     Twisted[tls,conch]>=18.4.0
+-    tahoe-lafs==1.14.0
++    tahoe-lafs
+     treq
+ 
+ [versioneer]
diff --git a/setup.cfg b/setup.cfg
index 371a19b343c204fb576b2c6d8c77d969160d40e3..dfc4960747ba2d57bea9b12deff72f59371cd743 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -36,9 +36,11 @@ install_requires =
     eliot
     aniso8601
     python-challenge-bypass-ristretto
-    # Inherit our Twisted dependency from tahoe-lafs so we don't accidentally
-    # get the extras wrong here and break stuff.
-    tahoe-lafs
+    # The pip resolver sometimes finds treq's dependencies first and these are
+    # incompatible with Tahoe-LAFS'.  So duplicate them here (the ones that
+    # have been observed to cause problems).
+    Twisted[tls,conch]>=18.4.0
+    tahoe-lafs==1.14.0
     treq
 
 [versioneer]
diff --git a/zkapauthorizer.nix b/zkapauthorizer.nix
index e76b19c5ebf03f74e6e04252ecfffa65f7cdaed0..89639e0d41ec84db5811503dd150f9c33250d0a3 100644
--- a/zkapauthorizer.nix
+++ b/zkapauthorizer.nix
@@ -27,6 +27,12 @@ buildPythonPackage rec {
     sphinx
   ];
 
+  patches = [
+    # Remove the Tahoe-LAFS version pin in distutils config.  We have our own
+    # pinning and also our Tahoe-LAFS package has a bogus version number. :/
+    ./nix/setup.cfg.patch
+  ];
+
   propagatedBuildInputs = [
     attrs
     zope_interface