diff --git a/pmtiles/makesync.go b/pmtiles/makesync.go
index 8236cbe..149f144 100644
--- a/pmtiles/makesync.go
+++ b/pmtiles/makesync.go
@@ -14,8 +14,10 @@ import (
 	"log"
 	"os"
 	"runtime"
+	"sort"
 	"strconv"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -129,7 +131,11 @@ func Makesync(logger *log.Logger, cli_version string, file string, block_size_kb
 	var current Block
 
 	tasks := make(chan Block, 10000)
-	intermediate := make(chan Result, 10000)
+
+	var wg sync.WaitGroup
+	var mu sync.Mutex
+
+	synclines := make(map[uint64]Syncline)
 
 	errs, _ := errgroup.WithContext(ctx)
 	// workers
@@ -147,47 +153,18 @@ func Makesync(logger *log.Logger, cli_version string, file string, block_size_kb
 				}
 				r.Close()
 
-				intermediate <- Result{block, hasher.Sum64()}
+				sum64 := hasher.Sum64()
+				mu.Lock()
+				synclines[block.Start] = Syncline{block.Offset, block.Length, sum64}
+				mu.Unlock()
+
 				hasher.Reset()
 			}
+			wg.Done()
 			return nil
 		})
 	}
 
-	done := make(chan struct{})
-
-	synclines := make([][]uint64, 0)
-
-	go func() {
-		buffer := make(map[uint64]Result)
-		nextIndex := uint64(0)
-
-		for i := range intermediate {
-			buffer[i.Block.Index] = i
-
-			for {
-				if next, ok := buffer[nextIndex]; ok {
-
-					// output.Write([]byte(fmt.Sprintf("%d\t%d\t%d\t%x\n", next.Block.Start, next.Block.Offset, next.Block.Length, next.Hash)))
-
-					synclines = append(synclines, []uint64{next.Block.Start, next.Block.Offset, next.Block.Length, next.Hash})
-
-					delete(buffer, nextIndex)
-					nextIndex++
-
-					if next.Block.Offset+next.Block.Length == header.TileDataLength {
-						close(intermediate)
-					}
-
-				} else {
-					break
-				}
-			}
-		}
-
-		done <- struct{}{}
-	}()
-
 	current_index := uint64(0)
 
 	blocks := 0
@@ -222,10 +199,17 @@ func Makesync(logger *log.Logger, cli_version string, file string, block_size_kb
 	blocks += 1
 	close(tasks)
 
-	<-done
+	wg.Wait()
+
+	var keys []uint64
+	for k := range synclines {
+		keys = append(keys, k)
+	}
+	sort.Slice(keys, func(i, j int) bool { return keys[i] < keys[j] })
 
-	for _, s := range synclines {
-		output.Write([]byte(fmt.Sprintf("%d\t%d\t%d\t%x\n", s[0], s[1], s[2], s[3])))
+	for _, k := range keys {
+		syncline := synclines[k]
+		output.Write([]byte(fmt.Sprintf("%d\t%d\t%d\t%x\n", k, syncline.Offset, syncline.Length, syncline.Hash)))
 	}
 
 	fmt.Printf("Created syncfile with %d blocks.\n", blocks)