diff --git a/cmd/htpacker/packer/packer.go b/cmd/htpacker/packer/packer.go
index 6dba182..00cc31e 100644
--- a/cmd/htpacker/packer/packer.go
+++ b/cmd/htpacker/packer/packer.go
@@ -325,14 +325,11 @@ func (p *packer) packFile(path string, fileToPack FileToPack) {
 		return
 	}
 
-	var data []byte
-	if fi.Size() > 0 {
-		data, err = unix.Mmap(int(f.Fd()), 0, int(fi.Size()),
-			unix.PROT_READ, unix.MAP_SHARED)
-		if err != nil {
-			p.Abort(fmt.Errorf("mmap %s: %v", fileToPack.Filename, err))
-			return
-		}
+	data, err := unix.Mmap(int(f.Fd()), 0, int(fi.Size()),
+		unix.PROT_READ, unix.MAP_SHARED)
+	if err != nil {
+		p.Abort(fmt.Errorf("mmap %s: %v", fileToPack.Filename, err))
+		return
 	}
 
 	// prepare initial directory entry
diff --git a/cmd/htpacker/yaml.go b/cmd/htpacker/yaml.go
index 37e10e1..eb8eaba 100644
--- a/cmd/htpacker/yaml.go
+++ b/cmd/htpacker/yaml.go
@@ -3,7 +3,6 @@ package main
 import (
 	"errors"
 	"fmt"
-	"io"
 	"io/ioutil"
 	"net/http"
 	"os"
@@ -126,22 +125,13 @@ func filesFromListR(prefix, arg string, ftp packer.FilesToPack) error {
 
 	case fi.Mode().IsRegular():
 		// sniff content type
-		var ctype string
 		buf := make([]byte, 512)
 		n, err := f.Read(buf)
-		switch err {
-		case nil:
-			buf = buf[:n]
-			ctype = http.DetectContentType(buf)
-
-		case io.EOF:
-			// Empty file; this is typically due to things like
-			// npm webpack producing empty .css files.
-			ctype = "text/plain; charset=UTF-8"
-
-		default:
-			return fmt.Errorf("failed to read %s: %v", arg, err)
+		if err != nil {
+			return err
 		}
+		buf = buf[:n]
+		ctype := http.DetectContentType(buf)
 
 		// augmented rules for JS / CSS / etc.
 		switch {