diff --git a/lfs.c b/lfs.c
index 66d9e782..eccd306a 100644
--- a/lfs.c
+++ b/lfs.c
@@ -1504,10 +1504,6 @@ static int lfsr_rbyd_lookup(lfs_t *lfs, const lfsr_rbyd_t *rbyd,
         lfsr_tag_t *tag_, lfs_ssize_t *id_, lfs_size_t *weight_,
         // TODO should this take lfsr_data_t for consistency?
         lfs_off_t *off_, lfs_size_t *size_) {
-    // tag must be non-zero! zero tags may deceptively look like they work but
-    // fail when the tree contains a deleted id0
-    LFS_ASSERT(tag != 0);
-
     // keep track of bounds as we descend down the tree
     lfs_off_t branch = rbyd->trunk;
     lfs_ssize_t lower = -1;
@@ -2284,13 +2280,13 @@ static int lfsr_rbyd_append(lfs_t *lfs, lfsr_rbyd_t *rbyd,
 
     } else if (tag == LFSR_TAG_GROW) {
         // decrease weight when growing
-        alt = LFSR_TAG_ALT(B, GT, 0);
+        alt = LFSR_TAG_ALT(B, LE, 0xfff0);
         weight = upper_id - lower_id - 1 + lfsr_data_len(data);
 
     } else if (tag == LFSR_TAG_SHRINK) {
         // decrease weight when shrinking
         if (upper_id - lower_id - 1 > (lfs_ssize_t)lfsr_data_len(data)) {
-            alt = LFSR_TAG_ALT(B, GT, 0);
+            alt = LFSR_TAG_ALT(B, LE, 0xfff0);
             weight = upper_id - lower_id - 1 - lfsr_data_len(data);
         }
 
@@ -2298,7 +2294,7 @@ static int lfsr_rbyd_append(lfs_t *lfs, lfsr_rbyd_t *rbyd,
             || (id_ == id && lfsr_tag_key(tag_) > lfsr_tag_key(tag))) {
         if (lfsr_tag_isrm(tag)) {
             // hide our tag during removes
-            alt = LFSR_TAG_ALT(B, GT, 0);
+            alt = LFSR_TAG_ALT(B, LE, 0xfff0);
             weight = upper_id - lower_id - 1;
         } else {
             // split greater than
@@ -2638,7 +2634,7 @@ static lfs_ssize_t lfsr_btree_lookup(lfs_t *lfs,
         lfs_size_t weight__;
         lfs_off_t off_;
         lfs_size_t size_;
-        err = lfsr_rbyd_lookup(lfs, &rbyd, LFSR_TAG_NAME, rid,
+        err = lfsr_rbyd_lookup(lfs, &rbyd, 0, rid,
                 &tag__, &rid__, &weight__, &off_, &size_);
         if (err) {
             return err;
@@ -2736,7 +2732,7 @@ static int lfsr_btree_parent(lfs_t *lfs,
         lfs_size_t weight__;
         lfs_off_t off_;
         lfs_size_t size_;
-        err = lfsr_rbyd_lookup(lfs, &rbyd, LFSR_TAG_NAME, rid,
+        err = lfsr_rbyd_lookup(lfs, &rbyd, 0, rid,
                 &tag__, &rid__, &weight__, &off_, &size_);
         if (err) {
             LFS_ASSERT(err != LFS_ERR_NOENT);
@@ -2860,7 +2856,7 @@ static lfs_ssize_t lfsr_btree_find_(lfs_t *lfs,
         lfs_size_t weight__;
         lfs_off_t off_;
         lfs_size_t size_;
-        err = lfsr_rbyd_lookup(lfs, &rbyd, LFSR_TAG_NAME, find.found_id,
+        err = lfsr_rbyd_lookup(lfs, &rbyd, 0, find.found_id,
                 &tag__, &rid__, &weight__, &off_, &size_);
         if (err) {
             return err;
diff --git a/scripts/dbgbtree.py b/scripts/dbgbtree.py
index bfcff549..a8522d74 100755
--- a/scripts/dbgbtree.py
+++ b/scripts/dbgbtree.py
@@ -309,7 +309,7 @@ def main(disk, block_size=None, trunk=0, limit=None, *,
             while True:
                 # first lookup id/name
                 (done, name_tag, rid_, w,
-                    name_j, name_d, name) = rbyd.lookup(TAG_NAME, rid)
+                    name_j, name_d, name) = rbyd.lookup(0, rid)
                 if done:
                     return (True, id, 0, rbyd, -1, 0,
                         0, 0, b'',
diff --git a/tests/test_rbyd.toml b/tests/test_rbyd.toml
index d6a9e25e..f7e020eb 100644
--- a/tests/test_rbyd.toml
+++ b/tests/test_rbyd.toml
@@ -2237,7 +2237,7 @@ code = '''
             LFSR_ATTR(UATTR(1), -1, "\xaa\xaa\xaa\xaa", 4,
             LFSR_ATTR(UATTR(2), -1, "\xbb\xbb\xbb\xbb", 4, NULL))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2251,7 +2251,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2271,7 +2271,7 @@ code = '''
             LFSR_ATTR(UATTR(2), -1, "\xbb\xbb\xbb\xbb", 4,
             LFSR_ATTR(UATTR(1), -1, "\xaa\xaa\xaa\xaa", 4, NULL))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2285,7 +2285,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2330,7 +2330,7 @@ code = '''
     lfsr_rbyd_commit(&lfs, &rbyd,
             LFSR_ATTR(UATTR(2), -1, "\xbb\xbb\xbb\xbb", 4, NULL)) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2344,7 +2344,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2365,7 +2365,7 @@ code = '''
     lfsr_rbyd_commit(&lfs, &rbyd,
             LFSR_ATTR(UATTR(1), -1, "\xaa\xaa\xaa\xaa", 4, NULL)) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -2379,7 +2379,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(1));
     assert(id_ == -1);
@@ -4424,7 +4424,7 @@ code = '''
             LFSR_ATTR(GROW, 1, NULL, 1,
             LFSR_ATTR(REG, 1, "\xbb\xbb\xbb\xbb", 4, NULL))))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4442,7 +4442,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4468,7 +4468,7 @@ code = '''
             LFSR_ATTR(GROW, 0, NULL, 1,
             LFSR_ATTR(REG, 0, "\xaa\xaa\xaa\xaa", 4, NULL))))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4486,7 +4486,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4538,7 +4538,7 @@ code = '''
             LFSR_ATTR(GROW, 1, NULL, 1,
             LFSR_ATTR(REG, 1, "\xbb\xbb\xbb\xbb", 4, NULL))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4556,7 +4556,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4583,7 +4583,7 @@ code = '''
             LFSR_ATTR(GROW, 0, NULL, 1,
             LFSR_ATTR(REG, 0, "\xaa\xaa\xaa\xaa", 4, NULL))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -4601,7 +4601,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5679,7 +5679,7 @@ code = '''
             LFSR_ATTR(REG,    1, "\xbb\xbb\xbb\xbb", 4,
             LFSR_ATTR(UATTR(1), 1, "\xbb\xbb",         2, NULL))))))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5711,7 +5711,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5753,7 +5753,7 @@ code = '''
             LFSR_ATTR(REG,    0, "\xaa\xaa\xaa\xaa", 4,
             LFSR_ATTR(UATTR(1), 0, "\xaa\xaa",         2, NULL))))))) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5785,7 +5785,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5855,7 +5855,7 @@ code = '''
     lfsr_rbyd_commit(&lfs, &rbyd,
             LFSR_ATTR(UATTR(1), 1, "\xbb\xbb",         2, NULL)) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5887,7 +5887,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5932,7 +5932,7 @@ code = '''
     lfsr_rbyd_commit(&lfs, &rbyd,
             LFSR_ATTR(UATTR(1), 0, "\xaa\xaa",         2, NULL)) => 0;
 
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -5964,7 +5964,7 @@ code = '''
             &tag_, &id_, NULL, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, NULL, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -8929,7 +8929,7 @@ code = '''
             NULL))))))))))) => 0;
 
     // traverse, finding tags and weights
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, &weight_, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -8963,7 +8963,7 @@ code = '''
             &tag_, &id_, &weight_, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, &weight_, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_REG);
     assert(id_ == 0);
@@ -9927,7 +9927,7 @@ code = '''
             NULL)))))))))))))))))))))))))) => 0;
 
     // traverse, finding tags and weights
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, &weight_, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(3));
     assert(id_ == -1);
@@ -10027,7 +10027,7 @@ code = '''
             &tag_, &id_, &weight_, &off_, &size_) => LFS_ERR_NOENT;
 
     lfsr_rbyd_fetch(&lfs, &rbyd, rbyd.block, cfg->block_size, NULL) => 0;
-    lfsr_rbyd_lookup(&lfs, &rbyd, lfsr_tag_next(0), -1,
+    lfsr_rbyd_lookup(&lfs, &rbyd, 0, -1,
             &tag_, &id_, &weight_, &off_, &size_) => 0;
     assert(tag_ == LFSR_TAG_UATTR(3));
     assert(id_ == -1);