diff --git a/pkgs/by-name/cv/cvc5/package.nix b/pkgs/by-name/cv/cvc5/package.nix
index 6436020f2c39..775bb1981bfa 100644
--- a/pkgs/by-name/cv/cvc5/package.nix
+++ b/pkgs/by-name/cv/cvc5/package.nix
@@ -18,13 +18,13 @@
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "cvc5";
-  version = "1.3.3";
+  version = "1.3.4";
 
   src = fetchFromGitHub {
     owner = "cvc5";
     repo = "cvc5";
     tag = "cvc5-${finalAttrs.version}";
-    hash = "sha256-tXhOMrf/sZwEZFWB2Amp9lApWEsfuPqaj9H7RmI733o=";
+    hash = "sha256-PZcOArSTyJzyd2DKT8K0aFC4RlVXgTCnkoU0f08KPfY=";
   };
 
   __structuredAttrs = true;
diff --git a/pkgs/by-name/is/isabelle/package.nix b/pkgs/by-name/is/isabelle/package.nix
index 0c48de36e306..a971e357825d 100644
--- a/pkgs/by-name/is/isabelle/package.nix
+++ b/pkgs/by-name/is/isabelle/package.nix
@@ -14,6 +14,7 @@
   eprover-ho,
   cvc5,
   libpoly,
+  symfpu,
   csdp,
   rlwrap,
   perl,
@@ -109,6 +110,10 @@ let
         version = "0.2.0";
         __intentionallyOverridingVersion = true;
       };
+      symfpu = symfpu.overrideAttrs {
+        version = "0-unstable-2019-05-17";
+        __intentionallyOverridingVersion = true;
+      };
     }).overrideAttrs
       {
         version = "1.2.0";
diff --git a/pkgs/by-name/sy/symfpu/package.nix b/pkgs/by-name/sy/symfpu/package.nix
index bfcd0553fd3c..f88d615873fa 100644
--- a/pkgs/by-name/sy/symfpu/package.nix
+++ b/pkgs/by-name/sy/symfpu/package.nix
@@ -8,13 +8,23 @@
 
 stdenv.mkDerivation (finalAttrs: {
   pname = "symfpu";
-  version = "0-unstable-2019-05-17";
+  version = "1.2.0-unstable-2026-05-13";
 
   src = fetchFromGitHub {
     owner = "martin-cs";
     repo = "symfpu";
-    rev = "8fbe139bf0071cbe0758d2f6690a546c69ff0053";
-    sha256 = "1jf5lkn67q136ppfacw3lsry369v7mdr1rhidzjpbz18jfy9zl9q";
+    rev =
+      {
+        "1.2.0-unstable-2026-05-13" = "40bdec00e99f8ea1b96c3dac0a05eed11c541639";
+        "0-unstable-2019-05-17" = "8fbe139bf0071cbe0758d2f6690a546c69ff0053";
+      }
+      ."${finalAttrs.version}";
+    hash =
+      {
+        "1.2.0-unstable-2026-05-13" = "sha256-ho0tLWFlPozq5hD+qX6AQiCPxUuRPwnXe9dEfzXwSY0=";
+        "0-unstable-2019-05-17" = "sha256-ONGfvJMo/HXlbxHmkFs9O5nhs6aDM+XuNSPgY+ykxck=";
+      }
+      ."${finalAttrs.version}";
   };
 
   nativeBuildInputs = [ copyPkgconfigItems ];
@@ -36,6 +46,8 @@ stdenv.mkDerivation (finalAttrs: {
     includedir = "${placeholder "out"}/include";
   };
 
+  dontBuild = true;
+
   installPhase = ''
     runHook preInstall