diff --git a/go/nix/bcacheup/bcacheup.go b/go/nix/bcacheup/bcacheup.go
index 3f7777504a..ab9d6f84e7 100644
--- a/go/nix/bcacheup/bcacheup.go
+++ b/go/nix/bcacheup/bcacheup.go
@@ -16,8 +16,8 @@ import (
 	"sync"
 	"time"
 
+	"github.com/jamespfennell/xz"
 	"github.com/numtide/go-nix/nixbase32"
-	"github.com/ulikunitz/xz"
 	"gocloud.dev/blob"
 	"golang.org/x/sync/errgroup"
 	"golang.org/x/sync/singleflight"
@@ -236,10 +236,7 @@ func (u *uploader) uploadContent(ctx context.Context, ni *narinfo.NarInfo, path
 
 	fileByteCounter := &byteCounterWriter{}
 
-	xzWriter, err := xz.NewWriter(io.MultiWriter(fileHasher, fileByteCounter, dst))
-	if err != nil {
-		return fmt.Errorf("creating xz writer: %v", err)
-	}
+	xzWriter := xz.NewWriter(io.MultiWriter(fileHasher, fileByteCounter, dst))
 
 	w := io.MultiWriter(narHasher, xzWriter)
 	narSize, err := nar.Pack(w, nar.DirFS(u.storePath), filepath.Base(path))
diff --git a/go/nix/bcacheup/default.nix b/go/nix/bcacheup/default.nix
index 54ae48cfb7..008d5f583c 100644
--- a/go/nix/bcacheup/default.nix
+++ b/go/nix/bcacheup/default.nix
@@ -14,7 +14,7 @@ depot.third_party.buildGo.program {
     third_party.gopkgs."gocloud.dev".blob.gcsblob
     third_party.gopkgs."golang.org".x.sync.errgroup
     third_party.gopkgs."golang.org".x.sync.singleflight
-    third_party.gopkgs."github.com".ulikunitz.xz
+    third_party.gopkgs."github.com".jamespfennell.xz
     go.nix.nar
     go.nix.nar.narinfo
     go.nix.nixstore
diff --git a/third_party/gopkgs/github.com/jamespfennell/xz/default.nix b/third_party/gopkgs/github.com/jamespfennell/xz/default.nix
new file mode 100644
index 0000000000..51d9a1285a
--- /dev/null
+++ b/third_party/gopkgs/github.com/jamespfennell/xz/default.nix
@@ -0,0 +1,18 @@
+# SPDX-FileCopyrightText: 2022 Luke Granger-Brown <depot@lukegb.com>
+#
+# SPDX-License-Identifier: Apache-2.0
+
+{ depot, pkgs, ... }:
+depot.third_party.buildGo.external {
+  path = "github.com/jamespfennell/xz";
+  src = depot.third_party.nixpkgs.fetchFromGitHub {
+    owner = "jamespfennell";
+    repo = "xz";
+    rev = "v0.1.2";
+    hash = "sha256:0wdxda81zvzvxvkxazkn48qlw62nhyc4am9vj2yvv9ncas4gp7av";
+  };
+  cgo = true;
+  cgodeps = [ pkgs.lzma ];
+  cgocflags = [ "-DGOXZ_SKIP_C_COMPILATION" ];
+  cgoldflags = [ "-llzma" ];
+}
diff --git a/third_party/tvl/nix/buildGo/external/default.nix b/third_party/tvl/nix/buildGo/external/default.nix
index c745507430..59a1109db2 100644
--- a/third_party/tvl/nix/buildGo/external/default.nix
+++ b/third_party/tvl/nix/buildGo/external/default.nix
@@ -50,7 +50,7 @@ let
 
   last = l: elemAt l ((length l) - 1);
 
-  toPackage = self: src: path: depMap: entry: cgodeps:
+  toPackage = self: src: path: depMap: entry: cgodeps: cgocflags: cgoldflags:
     let
       localDeps = map
         (d: lib.attrByPath (d ++ [ "gopkg" ])
@@ -79,7 +79,9 @@ let
         sfiles = map (f: src + ("/" + f)) entry.sfiles;
         cgofiles = map (f: src + ("/" + f)) entry.cgofiles;
         inherit cgodeps;
-        inherit (entry) packageName cgocflags cgoldflags;
+        cgocflags = entry.cgocflags ++ cgocflags;
+        cgoldflags = entry.cgoldflags ++ cgoldflags;
+        inherit (entry) packageName;
         cfiles = map (f: src + ("/" + f)) entry.cfiles;
         cxxfiles = map (f: src + ("/" + f)) entry.cxxfiles;
       };
@@ -91,7 +93,7 @@ let
     if entry.isCommand then (program binArgs) else (package libArgs);
 
 in
-{ src, path, deps ? [ ], tags ? [ ], cgo ? false, cgodeps ? [ ] }:
+{ src, path, deps ? [ ], tags ? [ ], cgo ? false, cgodeps ? [ ], cgocflags ? [ ], cgoldflags ? [ ] }:
 let
   # Build a map of dependencies (from their import paths to their
   # derivation) so that they can be conditionally imported only in
@@ -110,5 +112,5 @@ let
   analysis = fromJSON (readFile analysisOutput);
 in
 lib.fix (self: foldl' lib.recursiveUpdate { } (
-  map (entry: mkset entry.locator (toPackage self src path depMap entry cgodeps)) analysis
+  map (entry: mkset entry.locator (toPackage self src path depMap entry cgodeps cgocflags cgoldflags)) analysis
 ))
diff --git a/third_party/tvl/nix/buildGo/external/main.go b/third_party/tvl/nix/buildGo/external/main.go
index 7750acc016..795f0ba0c6 100644
--- a/third_party/tvl/nix/buildGo/external/main.go
+++ b/third_party/tvl/nix/buildGo/external/main.go
@@ -87,6 +87,13 @@ func findGoDirs(at string) ([]string, error) {
 	return goDirs, nil
 }
 
+func forceEmpty[T any](m []T) []T {
+	if m == nil {
+		return make([]T, 0)
+	}
+	return m
+}
+
 // analysePackage loads and analyses the imports of a single Go
 // package, returning the data that is required by the Nix code to
 // generate a derivation for this package.
@@ -153,8 +160,8 @@ func analysePackage(root, source, importpath string, stdlib map[string]bool, tag
 		LocalDeps:   local,
 		ForeignDeps: foreign,
 		IsCommand:   p.IsCommand(),
-		CgoCFLAGS:   p.CgoCFLAGS,
-		CgoLDFLAGS:  p.CgoLDFLAGS,
+		CgoCFLAGS:   forceEmpty(p.CgoCFLAGS),
+		CgoLDFLAGS:  forceEmpty(p.CgoLDFLAGS),
 	}, nil
 }