diff --git a/pkgs/build-support/fetchurl/mirrors.nix b/pkgs/build-support/fetchurl/mirrors.nix
index 7e51efed66ac..1a412617835f 100644
--- a/pkgs/build-support/fetchurl/mirrors.nix
+++ b/pkgs/build-support/fetchurl/mirrors.nix
@@ -93,9 +93,7 @@
   gnupg = [
     "https://gnupg.org/ftp/gcrypt/"
     "https://mirrors.dotsrc.org/gcrypt/"
-    "https://ftp.heanet.ie/mirrors/ftp.gnupg.org/gcrypt/"
     "https://www.mirrorservice.org/sites/ftp.gnupg.org/gcrypt/"
-    "http://www.ring.gr.jp/pub/net/"
   ];
 
   # IBiblio (former metalab/sunsite)
diff --git a/pkgs/tools/security/gnupg/24.nix b/pkgs/tools/security/gnupg/24.nix
index d2a9462b193a..680a9ff4b088 100644
--- a/pkgs/tools/security/gnupg/24.nix
+++ b/pkgs/tools/security/gnupg/24.nix
@@ -21,6 +21,7 @@
   readline,
   sqlite,
   zlib,
+  openssh,
   enableMinimal ? false,
   withPcsc ? !enableMinimal,
   pcsclite,
@@ -76,6 +77,7 @@ stdenv.mkDerivation rec {
     ]
     ++ lib.optionals withTpm2Tss [ tpm2-tss ];
 
+  # Maintained by Andrew Gallapher, who's involved with GPG in multiple ways: https://andrewg.com/
   freepgPatches = fetchFromGitLab {
     domain = "gitlab.com";
     owner = "freepg";
@@ -86,7 +88,16 @@ stdenv.mkDerivation rec {
 
   patches =
     [
+      # Without this, scdaemon isn't linked to libusb, causing smartcards to not work correctly
       ./fix-libusb-include-path.patch
+      # Use pkg-config to find tss2-esys to fix static building
+      # Submitted upstream: https://dev.gnupg.org/D606
+      # The diff is larger than upstream because configure.ac was modified,
+      # requiring configure to be regenerated. For reasons we don't totally
+      # understand, regenerating configure has all sorts of other undesirable
+      # side effects. So to unbreak things, instead of regenerating configure,
+      # we can include just the configure changes relevant to the static patch
+      # in the patch file.
       ./static.patch
     ]
     ++ lib.map (v: "${freepgPatches}/STABLE-BRANCH-2-4-freepg/" + v) [
@@ -116,6 +127,13 @@ stdenv.mkDerivation rec {
     ];
 
   postPatch =
+    # Switch the default key server to keys.openpgp.org
+    # The original motivation in 2019 was to switch away from the then-default SKS network: https://github.com/NixOS/nixpkgs/pull/63952
+    # In 2021 upstream also switched away, but to keyserver.ubuntu.com: https://dev.gnupg.org/rG47c4e3e00a7ef55f954c14b3c237496e54a853c1,
+    # while NixOS kept the keys.openpgp.org default: https://github.com/NixOS/nixpkgs/pull/159604
+    # TODO: Should this patch be removed so that the now-uncompromised default is used once again?
+    # A significant difference between the two seems to be that keys.openpgp.org is verifying keys, while keyserver.ubuntu.com isn't: https://unix.stackexchange.com/a/694528
+    # The keys.openpgp.org also has a great FAQ: https://keys.openpgp.org/about/faq
     ''
       sed -i 's,\(hkps\|https\)://keyserver.ubuntu.com,hkps://keys.openpgp.org,g' configure configure.ac doc/dirmngr.texi doc/gnupg.info-1
     ''
@@ -128,6 +146,8 @@ stdenv.mkDerivation rec {
   configureFlags =
     [
       "--sysconfdir=/etc"
+      # Needed for large RSA key support (patch 0033)
+      "--enable-large-secmem"
       "--with-libgpg-error-prefix=${libgpg-error.dev}"
       "--with-libgcrypt-prefix=${libgcrypt.dev}"
       "--with-libassuan-prefix=${libassuan.dev}"
@@ -163,6 +183,12 @@ stdenv.mkDerivation rec {
 
   enableParallelBuilding = true;
 
+  nativeCheckInputs = [
+    # A test would be skipped without SSH
+    openssh
+  ];
+  doCheck = !enableMinimal;
+
   passthru.tests = nixosTests.gnupg;
 
   meta = with lib; {