diff --git a/nix/pkgs/main/cross-compilation-env.nix b/nix/pkgs/main/cross-compilation-env.nix
index 3f4d593b..83fe6ed6 100644
--- a/nix/pkgs/main/cross-compilation-env.nix
+++ b/nix/pkgs/main/cross-compilation-env.nix
@@ -13,12 +13,6 @@ lib.optionalAttrs stdenv.hostPlatform.isStatic {
     lib.concatStringsSep
       " "
       ([]
-        ++ lib.optionals
-          stdenv.targetPlatform.isx86_64
-          [ "-C" "target-cpu=x86-64-v2" ]
-        ++ lib.optionals
-          stdenv.targetPlatform.isAarch64
-          [ "-C" "target-cpu=cortex-a53" ] # cortex-a53 == ARMv8-A
         # This disables PIE for static builds, which isn't great in terms
         # of security. Unfortunately, my hand is forced because nixpkgs'
         # `libstdc++.a` is built without `-fPIE`, which precludes us from
diff --git a/nix/pkgs/main/default.nix b/nix/pkgs/main/default.nix
index 31a2b7aa..8559e878 100644
--- a/nix/pkgs/main/default.nix
+++ b/nix/pkgs/main/default.nix
@@ -83,24 +83,6 @@ buildDepsOnlyEnv =
       meta.broken = stdenv.hostPlatform.isStatic && stdenv.isDarwin;
 
       enableLiburing = enableLiburing;
-
-      sse42Support = stdenv.targetPlatform.isx86_64;
-
-      cmakeFlags = if stdenv.targetPlatform.isx86_64
-        then lib.subtractLists [ "-DPORTABLE=1" ] old.cmakeFlags
-        ++ lib.optionals stdenv.targetPlatform.isx86_64 [
-          "-DPORTABLE=x86-64-v2"
-          "-DUSE_SSE=1"
-          "-DHAVE_SSE=1"
-          "-DHAVE_SSE42=1"
-        ]
-        else if stdenv.targetPlatform.isAarch64
-        then lib.subtractLists [ "-DPORTABLE=1" ] old.cmakeFlags
-        ++ lib.optionals stdenv.targetPlatform.isAarch64 [
-          # cortex-a53 == ARMv8-A
-          "-DPORTABLE=armv8-a"
-        ]
-        else old.cmakeFlags;
     });
   in
   {
@@ -127,11 +109,7 @@ buildPackageEnv = {
   # Only needed in static stdenv because these are transitive dependencies of rocksdb
   CARGO_BUILD_RUSTFLAGS = buildDepsOnlyEnv.CARGO_BUILD_RUSTFLAGS
     + lib.optionalString (enableLiburing && stdenv.hostPlatform.isStatic)
-      " -L${lib.getLib liburing}/lib -luring"
-    + lib.optionalString stdenv.targetPlatform.isx86_64
-      " -Ctarget-cpu=x86-64-v2"
-    + lib.optionalString stdenv.targetPlatform.isAarch64
-      " -Ctarget-cpu=cortex-a53"; # cortex-a53 == ARMv8-A
+      " -L${lib.getLib liburing}/lib -luring";
 };