diff --git a/kittens/unicode_input/main.go b/kittens/unicode_input/main.go
index 42cfe8f92..24cd8b7fa 100644
--- a/kittens/unicode_input/main.go
+++ b/kittens/unicode_input/main.go
@@ -3,6 +3,7 @@
 package unicode_input
 
 import (
+	"bytes"
 	"errors"
 	"fmt"
 	"os"
@@ -442,7 +443,7 @@ func (self *handler) handle_favorites_key_event(event *loop.KeyEvent) {
 				self.lp.Quit(1)
 				return
 			}
-			err = utils.AtomicUpdateFile(fp, utils.UnsafeStringToBytes(raw), 0o600)
+			err = utils.AtomicUpdateFile(fp, bytes.NewReader(utils.UnsafeStringToBytes(raw)), 0o600)
 			if err != nil {
 				self.err = fmt.Errorf("Failed to write to favorites file %s with error: %w", fp, err)
 				self.lp.Quit(1)
diff --git a/tools/cmd/edit_in_kitty/main.go b/tools/cmd/edit_in_kitty/main.go
index fb4929d4d..af339a615 100644
--- a/tools/cmd/edit_in_kitty/main.go
+++ b/tools/cmd/edit_in_kitty/main.go
@@ -3,6 +3,7 @@
 package edit_in_kitty
 
 import (
+	"bytes"
 	"encoding/base64"
 	"fmt"
 	"io"
@@ -212,7 +213,7 @@ func edit_in_kitty(path string, opts *Options) (err error) {
 	add_encoded("file_data", utils.UnsafeBytesToString(file_data))
 	fmt.Println("Waiting for editing to be completed, press Esc to abort...")
 	write_data := func(data_type string, rdata []byte) (err error) {
-		err = utils.AtomicWriteFile(path, rdata, fs.FileMode(s.Mode).Perm())
+		err = utils.AtomicWriteFile(path, bytes.NewReader(rdata), fs.FileMode(s.Mode).Perm())
 		if err != nil {
 			err = fmt.Errorf("Failed to write data to %s with error: %w", path, err)
 		}
diff --git a/tools/config/api.go b/tools/config/api.go
index f2f0dea84..bd442742f 100644
--- a/tools/config/api.go
+++ b/tools/config/api.go
@@ -344,7 +344,7 @@ func (self Patcher) Patch(path, sentinel, content string, settings_to_comment_ou
 			_ = os.WriteFile(backup_path+".bak", raw, self.Mode)
 		}
 
-		return true, utils.AtomicUpdateFile(path, nraw, self.Mode)
+		return true, utils.AtomicUpdateFile(path, bytes.NewReader(nraw), self.Mode)
 	}
 	return false, nil
 }
diff --git a/tools/themes/collection.go b/tools/themes/collection.go
index 02a846c5a..6e6be02f6 100644
--- a/tools/themes/collection.go
+++ b/tools/themes/collection.go
@@ -344,7 +344,7 @@ func set_comment_in_zip_file(path string, comment string) error {
 		}
 	}
 	dest.Close()
-	return utils.AtomicUpdateFile(path, buf.Bytes(), 0o644)
+	return utils.AtomicUpdateFile(path, bytes.NewReader(buf.Bytes()), 0o644)
 }
 
 func fetch_cached(name, url, cache_path string, max_cache_age time.Duration) (string, error) {
@@ -584,7 +584,7 @@ func (self *Theme) SaveInDir(dirpath string) (err error) {
 	if err != nil {
 		return err
 	}
-	return utils.AtomicUpdateFile(path, utils.UnsafeStringToBytes(code), 0o644)
+	return utils.AtomicUpdateFile(path, bytes.NewReader(utils.UnsafeStringToBytes(code)), 0o644)
 }
 
 func (self *Theme) SaveInConf(config_dir, reload_in, config_file_name string) (err error) {
@@ -594,7 +594,7 @@ func (self *Theme) SaveInConf(config_dir, reload_in, config_file_name string) (e
 	if err != nil {
 		return err
 	}
-	err = utils.AtomicUpdateFile(path, utils.UnsafeStringToBytes(code), 0o644)
+	err = utils.AtomicUpdateFile(path, bytes.NewReader(utils.UnsafeStringToBytes(code)), 0o644)
 	if err != nil {
 		return err
 	}
diff --git a/tools/tui/shell_integration/api.go b/tools/tui/shell_integration/api.go
index ad57a7b06..f07b14026 100644
--- a/tools/tui/shell_integration/api.go
+++ b/tools/tui/shell_integration/api.go
@@ -50,7 +50,7 @@ func extract_files(match, dest_dir string) (err error) {
 			if existing, rerr := os.ReadFile(dest); rerr == nil && bytes.Equal(existing, entry.Data) {
 				continue
 			}
-			if err = utils.AtomicWriteFile(dest, entry.Data, 0o644); err != nil {
+			if err = utils.AtomicWriteFile(dest, bytes.NewReader(entry.Data), 0o644); err != nil {
 				return
 			}
 		}
diff --git a/tools/utils/atomic-write.go b/tools/utils/atomic-write.go
index 17fb0a7db..eb7b7d2ab 100644
--- a/tools/utils/atomic-write.go
+++ b/tools/utils/atomic-write.go
@@ -5,6 +5,7 @@ package utils
 import (
 	"errors"
 	"fmt"
+	"io"
 	"io/fs"
 	"os"
 	"path/filepath"
@@ -39,7 +40,7 @@ func AtomicCreateSymlink(oldname, newname string) (err error) {
 	}
 }
 
-func AtomicWriteFile(path string, data []byte, perm os.FileMode) (err error) {
+func AtomicWriteFile(path string, data io.Reader, perm os.FileMode) (err error) {
 	npath, err := filepath.EvalSymlinks(path)
 	if errors.Is(err, fs.ErrNotExist) {
 		err = nil
@@ -60,7 +61,7 @@ func AtomicWriteFile(path string, data []byte, perm os.FileMode) (err error) {
 						removed = true
 					}
 				}()
-				_, err = f.Write(data)
+				_, err = io.Copy(f, data)
 				if err == nil {
 					err = f.Chmod(perm)
 					if err == nil {
@@ -76,7 +77,7 @@ func AtomicWriteFile(path string, data []byte, perm os.FileMode) (err error) {
 	return
 }
 
-func AtomicUpdateFile(path string, data []byte, perms ...fs.FileMode) (err error) {
+func AtomicUpdateFile(path string, data io.Reader, perms ...fs.FileMode) (err error) {
 	perm := fs.FileMode(0o644)
 	if len(perms) > 0 {
 		perm = perms[0]
diff --git a/tools/utils/cached_values.go b/tools/utils/cached_values.go
index ced751557..d86ace74b 100644
--- a/tools/utils/cached_values.go
+++ b/tools/utils/cached_values.go
@@ -3,6 +3,7 @@
 package utils
 
 import (
+	"bytes"
 	"encoding/json"
 	"fmt"
 	"os"
@@ -31,7 +32,7 @@ func (self *CachedValues[T]) Load() T {
 func (self *CachedValues[T]) Save() {
 	raw, err := json.Marshal(self.Opts)
 	if err == nil {
-		AtomicUpdateFile(self.Path(), raw, 0o600)
+		AtomicUpdateFile(self.Path(), bytes.NewReader(raw), 0o600)
 	}
 }