diff --git a/block/block_manager.go b/block/block_manager.go
index d537662f4..014dc13e6 100644
--- a/block/block_manager.go
+++ b/block/block_manager.go
@@ -750,7 +750,7 @@ func (bm *Manager) writePackDataNotLocked(ctx context.Context, data []byte) (str
 		return "", fmt.Errorf("unable to read crypto bytes: %v", err)
 	}
 
-	physicalBlockID := string(fmt.Sprintf("%v%x", PackBlockPrefix, blockID))
+	physicalBlockID := fmt.Sprintf("%v%x", PackBlockPrefix, blockID)
 
 	atomic.AddInt32(&bm.stats.WrittenBlocks, 1)
 	atomic.AddInt64(&bm.stats.WrittenBytes, int64(len(data)))
@@ -763,7 +763,7 @@ func (bm *Manager) writePackDataNotLocked(ctx context.Context, data []byte) (str
 
 func (bm *Manager) encryptAndWriteBlockNotLocked(ctx context.Context, data []byte, prefix string) (string, error) {
 	hash := bm.hashData(data)
-	physicalBlockID := string(prefix + hex.EncodeToString(hash))
+	physicalBlockID := prefix + hex.EncodeToString(hash)
 
 	// Encrypt the block in-place.
 	atomic.AddInt64(&bm.stats.EncryptedBytes, int64(len(data)))
@@ -900,7 +900,7 @@ func (bm *Manager) decryptAndVerifyPayload(formatVersion byte, payload []byte, o
 }
 
 func (bm *Manager) getPhysicalBlockInternal(ctx context.Context, blockID string) ([]byte, error) {
-	payload, err := bm.cache.getBlock(ctx, string(blockID), blockID, 0, -1)
+	payload, err := bm.cache.getBlock(ctx, blockID, blockID, 0, -1)
 	if err != nil {
 		return nil, err
 	}
@@ -932,8 +932,7 @@ func getPackedBlockIV(blockID string) ([]byte, error) {
 	return hex.DecodeString(blockID[len(blockID)-(aes.BlockSize*2):])
 }
 
-func getPhysicalBlockIV(b string) ([]byte, error) {
-	s := string(b)
+func getPhysicalBlockIV(s string) ([]byte, error) {
 	if p := strings.Index(s, "-"); p >= 0 {
 		s = s[0:p]
 	}
@@ -993,7 +992,7 @@ func listIndexBlocksFromStorage(ctx context.Context, st storage.Storage) ([]Inde
 		}
 
 		ii := IndexInfo{
-			FileName:  string(it.BlockID),
+			FileName:  it.BlockID,
 			Timestamp: it.TimeStamp,
 			Length:    it.Length,
 		}
diff --git a/block/local_storage_cache.go b/block/local_storage_cache.go
index b2dfdc4c5..f8bbefb90 100644
--- a/block/local_storage_cache.go
+++ b/block/local_storage_cache.go
@@ -51,7 +51,7 @@ func (c *localStorageCache) getBlock(ctx context.Context, cacheKey string, physi
 		log.Warn().Msgf("unable to read cache %v: %v", cacheKey, err)
 	}
 
-	b, err = c.st.GetBlock(ctx, string(physicalBlockID), offset, length)
+	b, err = c.st.GetBlock(ctx, physicalBlockID, offset, length)
 	if err == storage.ErrBlockNotFound {
 		// not found in underlying storage
 		return nil, err
@@ -76,12 +76,12 @@ func (c *localStorageCache) writeToCacheBestEffort(ctx context.Context, cacheKey
 
 func (c *localStorageCache) putBlock(ctx context.Context, blockID string, data []byte) error {
 	c.deleteListCache(ctx)
-	return c.st.PutBlock(ctx, string(blockID), bytes.NewReader(data))
+	return c.st.PutBlock(ctx, blockID, bytes.NewReader(data))
 }
 
 func (c *localStorageCache) deleteBlock(ctx context.Context, blockID string) error {
 	c.deleteListCache(ctx)
-	return c.st.DeleteBlock(ctx, string(blockID))
+	return c.st.DeleteBlock(ctx, blockID)
 }
 
 func (c *localStorageCache) listIndexBlocks(ctx context.Context) ([]IndexInfo, error) {
diff --git a/block/null_block_cache.go b/block/null_block_cache.go
index 5fc7bfd67..5e9018ea1 100644
--- a/block/null_block_cache.go
+++ b/block/null_block_cache.go
@@ -12,11 +12,11 @@ type nullBlockCache struct {
 }
 
 func (c nullBlockCache) getBlock(ctx context.Context, cacheKey string, blockID string, offset, length int64) ([]byte, error) {
-	return c.st.GetBlock(ctx, string(blockID), offset, length)
+	return c.st.GetBlock(ctx, blockID, offset, length)
 }
 
 func (c nullBlockCache) putBlock(ctx context.Context, blockID string, data []byte) error {
-	return c.st.PutBlock(ctx, string(blockID), bytes.NewReader(data))
+	return c.st.PutBlock(ctx, blockID, bytes.NewReader(data))
 }
 
 func (c nullBlockCache) listIndexBlocks(ctx context.Context) ([]IndexInfo, error) {
@@ -27,7 +27,7 @@ func (c nullBlockCache) deleteListCache(ctx context.Context) {
 }
 
 func (c nullBlockCache) deleteBlock(ctx context.Context, blockID string) error {
-	return c.st.DeleteBlock(ctx, string(blockID))
+	return c.st.DeleteBlock(ctx, blockID)
 }
 
 func (c nullBlockCache) close() error {
diff --git a/block/simple_committed_block_index.go b/block/simple_committed_block_index.go
index 58c6ee09f..e1672f4c9 100644
--- a/block/simple_committed_block_index.go
+++ b/block/simple_committed_block_index.go
@@ -57,7 +57,7 @@ func (b *simpleCommittedBlockIndex) hasIndexBlockID(indexBlockID string) (bool,
 }
 
 func (b *simpleCommittedBlockIndex) indexBlockPath(indexBlockID string) string {
-	return filepath.Join(b.dirname, string(indexBlockID+simpleIndexSuffix))
+	return filepath.Join(b.dirname, indexBlockID+simpleIndexSuffix)
 }
 
 func (b *simpleCommittedBlockIndex) addBlockToCache(indexBlockID string, data []byte) error {
@@ -159,7 +159,7 @@ func (b *simpleCommittedBlockIndex) use(packFiles []string) error {
 	}
 
 	for _, e := range packFiles {
-		fname := string(e) + simpleIndexSuffix
+		fname := e + simpleIndexSuffix
 		delete(remaining, fname)
 		fullpath := filepath.Join(b.dirname, fname)
 		ndx, err := b.openIndex(fullpath)
diff --git a/cli/analytics.go b/cli/analytics.go
index bc8a959ee..c21d36564 100644
--- a/cli/analytics.go
+++ b/cli/analytics.go
@@ -24,7 +24,7 @@
 
 var (
 	clientIDFile     = app.Flag("client-id-file", "Path to client ID file, which enables anonymous usage reporting if present").Default(filepath.Join(ospath.ConfigDir(), "client_id.txt")).String()
-	analyticsConsent = app.Flag("analytics-consent", "Consent to send analytics").Default("ask").Enum("yes", "no", "ask")
+	analyticsConsent = app.Flag("analytics-consent", "Consent to send analytics").Default("ask").Enum("agree", "disagree", "ask")
 
 	globalGAClient *ga.Client
 	gaClientOnce   sync.Once
@@ -79,10 +79,10 @@ func promptForAnalyticsConsent() {
 	clientID := fmt.Sprintf("%x", x)
 
 	switch *analyticsConsent {
-	case "no":
+	case "disagree":
 		disableAnalytics()
 
-	case "yes":
+	case "agree":
 		enableAnalytics(clientID)
 
 	case "ask":
diff --git a/cli/command_block_gc.go b/cli/command_block_gc.go
index 3b52b91f8..27cc44117 100644
--- a/cli/command_block_gc.go
+++ b/cli/command_block_gc.go
@@ -4,7 +4,6 @@
 	"context"
 	"fmt"
 	"os"
-	"strings"
 
 	"github.com/kopia/kopia/block"
 	"github.com/kopia/kopia/repo"
@@ -23,7 +22,7 @@ func runBlockGarbageCollectAction(ctx context.Context, rep *repo.Repository) err
 	}
 
 	usedPackBlocks := findPackBlocksInUse(infos)
-	ch := rep.Storage.ListBlocks(ctx, "")
+	ch := rep.Storage.ListBlocks(ctx, block.PackBlockPrefix)
 
 	var unused []string
 	var totalBytes int64
@@ -33,22 +32,15 @@ func runBlockGarbageCollectAction(ctx context.Context, rep *repo.Repository) err
 			return fmt.Errorf("error listing storage blocks: %v", bi.Error)
 		}
 
-		if strings.HasPrefix(bi.BlockID, "n") {
-			continue
-		}
-		if strings.HasPrefix(bi.BlockID, "kopia") {
-			continue
-		}
-
 		allPackBlocks++
 
-		u := usedPackBlocks[string(bi.BlockID)]
+		u := usedPackBlocks[bi.BlockID]
 		if u > 0 {
 			log.Printf("pack %v, in use by %v blocks", bi.BlockID, u)
 			continue
 		}
 
-		totalBytes += int64(bi.Length)
+		totalBytes += bi.Length
 		unused = append(unused, bi.BlockID)
 	}
 	fmt.Fprintf(os.Stderr, "Found %v/%v pack blocks in use.\n", len(usedPackBlocks), allPackBlocks)
diff --git a/cli/command_block_index_show.go b/cli/command_block_index_show.go
index e0dbd9a51..c5b6392a6 100644
--- a/cli/command_block_index_show.go
+++ b/cli/command_block_index_show.go
@@ -21,9 +21,8 @@
 
 func getIndexBlocksToShow(ctx context.Context, rep *repo.Repository) ([]string, error) {
 	var blockIDs []string
-	for _, id := range *blockIndexShowIDs {
-		blockIDs = append(blockIDs, string(id))
-	}
+
+	blockIDs = append(blockIDs, *blockIndexShowIDs...)
 
 	if len(blockIDs) == 1 && blockIDs[0] == "active" {
 		b, err := rep.Blocks.IndexBlocks(ctx)
diff --git a/cli/command_block_rewrite.go b/cli/command_block_rewrite.go
index ebc5379e4..29bdd17d0 100644
--- a/cli/command_block_rewrite.go
+++ b/cli/command_block_rewrite.go
@@ -55,52 +55,88 @@ func runRewriteBlocksAction(ctx context.Context, rep *repo.Repository) error {
 }
 
 func getBlocksToRewrite(ctx context.Context, rep *repo.Repository) ([]block.Info, error) {
+	// get blocks listed on command line
+	result, err := getBlockInfos(ctx, rep, *blockRewriteIDs)
+	if err != nil {
+		return nil, err
+	}
+
+	// add all blocks from short packs
+	if *blockRewriteShortPacks {
+		threshold := uint32(rep.Blocks.Format.MaxPackSize * 6 / 10)
+		info, err := getBlocksInShortPacks(ctx, rep, threshold)
+		if err != nil {
+			return nil, err
+		}
+
+		result = append(result, info...)
+	}
+
+	// add all blocks with given format version
+	if *blockRewriteFormatVersion != -1 {
+		info, err := getBlocksWithFormatVersion(ctx, rep, *blockRewriteFormatVersion)
+		if err != nil {
+			return nil, err
+		}
+
+		result = append(result, info...)
+	}
+
+	return result, nil
+}
+
+func getBlockInfos(ctx context.Context, rep *repo.Repository, blockIDs []string) ([]block.Info, error) {
 	var result []block.Info
-	for _, blockID := range *blockRewriteIDs {
+	for _, blockID := range blockIDs {
 		i, err := rep.Blocks.BlockInfo(ctx, blockID)
 		if err != nil {
 			return nil, fmt.Errorf("unable to get info for block %q: %v", blockID, err)
 		}
 		result = append(result, i)
 	}
+	return result, nil
+}
 
-	if *blockRewriteShortPacks {
-		infos, err := rep.Blocks.ListBlockInfos("", true)
-		if err != nil {
-			return nil, fmt.Errorf("unable to list index blocks: %v", err)
-		}
+func getBlocksWithFormatVersion(ctx context.Context, rep *repo.Repository, version int) ([]block.Info, error) {
+	var result []block.Info
 
-		threshold := uint32(rep.Blocks.Format.MaxPackSize * 6 / 10)
-		shortPackBlocks, err := findShortPackBlocks(infos, threshold)
-		if err != nil {
-			return nil, fmt.Errorf("unable to find short pack blocks: %v", err)
-		}
-		log.Printf("found %v short pack blocks", len(shortPackBlocks))
+	infos, err := rep.Blocks.ListBlockInfos("", true)
+	if err != nil {
+		return nil, fmt.Errorf("unable to list index blocks: %v", err)
+	}
 
-		if len(shortPackBlocks) <= 1 {
-			fmt.Printf("Nothing to do, found %v short pack blocks\n", len(shortPackBlocks))
-		} else {
-			for _, b := range infos {
-				if shortPackBlocks[b.PackFile] && strings.HasPrefix(string(b.PackFile), *blockRewritePackPrefix) {
-					result = append(result, b)
-				}
-			}
+	for _, b := range infos {
+		if int(b.FormatVersion) == *blockRewriteFormatVersion && strings.HasPrefix(b.PackFile, *blockRewritePackPrefix) {
+			result = append(result, b)
 		}
 	}
 
-	if *blockRewriteFormatVersion != -1 {
-		infos, err := rep.Blocks.ListBlockInfos("", true)
-		if err != nil {
-			return nil, fmt.Errorf("unable to list index blocks: %v", err)
-		}
+	return result, nil
+}
 
+func getBlocksInShortPacks(ctx context.Context, rep *repo.Repository, threshold uint32) ([]block.Info, error) {
+	var result []block.Info
+
+	infos, err := rep.Blocks.ListBlockInfos("", true)
+	if err != nil {
+		return nil, fmt.Errorf("unable to list index blocks: %v", err)
+	}
+
+	shortPackBlocks, err := findShortPackBlocks(infos, threshold)
+	if err != nil {
+		return nil, fmt.Errorf("unable to find short pack blocks: %v", err)
+	}
+	log.Printf("found %v short pack blocks", len(shortPackBlocks))
+
+	if len(shortPackBlocks) <= 1 {
+		fmt.Printf("Nothing to do, found %v short pack blocks\n", len(shortPackBlocks))
+	} else {
 		for _, b := range infos {
-			if int(b.FormatVersion) == *blockRewriteFormatVersion && strings.HasPrefix(string(b.PackFile), *blockRewritePackPrefix) {
+			if shortPackBlocks[b.PackFile] && strings.HasPrefix(b.PackFile, *blockRewritePackPrefix) {
 				result = append(result, b)
 			}
 		}
 	}
-
 	return result, nil
 }