diff --git a/src/cu.h b/src/cu.h
index 3f70df25..96897b62 100644
--- a/src/cu.h
+++ b/src/cu.h
@@ -597,5 +597,6 @@ static INLINE void cbf_copy(uint16_t *cbf, uint16_t src, color_t plane)
 }
 
 #define GET_SPLITDATA(CU,curDepth) (((CU)->split_tree >> (curDepth)) & 7)
+#define PU_IS_TU(cu) ((cu)->log2_width <= TR_MAX_LOG2_SIZE && (cu)->log2_height <= TR_MAX_LOG2_SIZE)
 
 #endif
diff --git a/src/encode_coding_tree.c b/src/encode_coding_tree.c
index 2556c950..4ee820c0 100644
--- a/src/encode_coding_tree.c
+++ b/src/encode_coding_tree.c
@@ -109,86 +109,32 @@ static void encode_mts_idx(
 bool uvg_is_lfnst_allowed(
   const encoder_state_t* const state,
   const cu_info_t* const pred_cu,
-  const int width,
-  const int height,
-  const int x,
-  const int y,
   enum uvg_tree_type tree_type,
   const color_t color,
-  const lcu_t* lcu) 
+  const cu_loc_t* const cu_loc) 
 {
-  if (state->encoder_control->cfg.lfnst && pred_cu->type == CU_INTRA && pred_cu->depth == pred_cu->tr_depth) {
+  if (state->encoder_control->cfg.lfnst && pred_cu->type == CU_INTRA && PU_IS_TU(pred_cu)) {
     const int isp_mode = pred_cu->intra.isp_mode;
-    const int depth = pred_cu->depth;
-    const int chroma_width = width >> 1;
-    const int chroma_height = height >> 1;
-    const int cu_width = tree_type != UVG_LUMA_T || depth == 4 ? width : chroma_width;
-    const int cu_height = tree_type != UVG_LUMA_T || depth == 4 ? height : chroma_height;
-    bool can_use_lfnst_with_mip = (width >= 16 && height >= 16);
-    bool is_sep_tree = depth == 4 || tree_type != UVG_BOTH_T;
+    const int cu_width = tree_type != UVG_CHROMA_T ? cu_loc->width : cu_loc->chroma_width;
+    const int cu_height = tree_type != UVG_CHROMA_T ? cu_loc->height : cu_loc->chroma_height;
+    bool can_use_lfnst_with_mip = (cu_width >= 16 && cu_height >= 16);
+    bool is_sep_tree = tree_type != UVG_BOTH_T;
     bool mip_flag = pred_cu->type == CU_INTRA && color == COLOR_Y ? pred_cu->intra.mip_flag : false;
 
-    if ((isp_mode && !uvg_can_use_isp_with_lfnst(width, height, isp_mode, tree_type)) ||
+    if ((isp_mode && !uvg_can_use_isp_with_lfnst(cu_width, cu_height, isp_mode, tree_type)) ||
       (pred_cu->type == CU_INTRA && mip_flag && !can_use_lfnst_with_mip) || 
       (is_sep_tree && MIN(cu_width, cu_height) < 4) || 
       (cu_width > TR_MAX_WIDTH || cu_height > TR_MAX_WIDTH)) {
       return false;
     }
-    bool luma_flag = (depth == 4 && color == COLOR_Y) || (tree_type != UVG_CHROMA_T && depth != 4);
-    bool chroma_flag = (depth == 4 && color != COLOR_Y) || tree_type != UVG_LUMA_T;
+    bool luma_flag = tree_type != UVG_CHROMA_T;
+    bool chroma_flag = tree_type != UVG_LUMA_T;
     bool non_zero_coeff_non_ts_corner_8x8 = false;
     bool last_scan_pos = false;
     bool is_tr_skip = false;
-
-    int split_num = color == COLOR_Y && isp_mode ? uvg_get_isp_split_num(width, height, isp_mode, false) : 0;
-    const videoframe_t* const frame = state->tile->frame;
     
-    if (split_num) {
-      // Constraints for ISP split blocks
-      for (int i = 0; i < split_num; ++i) {
-        cu_loc_t split_loc;
-        uvg_get_isp_split_loc(&split_loc, x, y, width, height, i, isp_mode, false);
-        int local_split_x = split_loc.x;
-        int local_split_y = split_loc.y;
-        uvg_get_isp_cu_arr_coords(&local_split_x, &local_split_y);
-        const cu_info_t* split_cu = lcu ? LCU_GET_CU_AT_PX(lcu, local_split_x, local_split_y) : 
-                                    uvg_cu_array_at_const(frame->cu_array, local_split_x, local_split_y);
-
-        //if (cbf_is_set(split_cu->cbf, depth, COLOR_Y)) {
-        // ISP_TODO: remove this if clause altogether if it seems it is not needed
-        if (true) {
-          non_zero_coeff_non_ts_corner_8x8 |= (luma_flag && split_cu->violates_lfnst_constrained_luma) || (chroma_flag && split_cu->violates_lfnst_constrained_chroma);
-          //last_scan_pos |= split_cu->lfnst_last_scan_pos;
-          last_scan_pos |= true;
-        }
-      }
-    } else {
-      non_zero_coeff_non_ts_corner_8x8 |= (luma_flag && pred_cu->violates_lfnst_constrained_luma) || (chroma_flag && pred_cu->violates_lfnst_constrained_chroma);
-      last_scan_pos |= pred_cu->lfnst_last_scan_pos;
-    }
-
-    //const int num_pred_units = kvz_part_mode_num_parts[pred_cu->part_size];
-    const int tr_depth = pred_cu->tr_depth;
-    assert(depth <= tr_depth && "Depth greater than transform depth. This should never trigger.");
-    const int num_transform_units = 1 << (2 * (tr_depth - depth));
-    const int tu_row_length = 1 << (tr_depth - depth);
-    const int tu_width = cu_width >> (tr_depth - depth);
-    const int tu_height = tu_width; // TODO: height for non-square blocks
-
-    // TODO: chroma transform skip
-    if (color == COLOR_Y) {
-      for (int i = 0; i < num_transform_units; i++) {
-        // TODO: this works only for square blocks
-        const int tu_x = x + ((i % tu_row_length) * tu_width);
-        const int tu_y = y + ((i / tu_row_length) * tu_height);
-        const cu_info_t* cur_tu = lcu ? LCU_GET_CU_AT_PX(lcu, tu_x, tu_y) : uvg_cu_array_at_const(frame->cu_array, tu_x, tu_y);
-        assert(cur_tu != NULL && "NULL transform unit.");
-        bool cbf_set = cbf_is_set(cur_tu->cbf, tr_depth, COLOR_Y);
-
-        if (cur_tu != NULL && cbf_set && cur_tu->tr_idx == MTS_SKIP) {
-          is_tr_skip = true;
-        }
-      }
+    if (color == COLOR_Y && pred_cu->tr_idx == MTS_SKIP) {
+      is_tr_skip = true;
     }
 
     if ((!pred_cu->lfnst_last_scan_pos && !isp_mode) || non_zero_coeff_non_ts_corner_8x8 || is_tr_skip) {
@@ -205,19 +151,15 @@ static bool encode_lfnst_idx(
   const encoder_state_t* const state,
   cabac_data_t * const cabac,
   const cu_info_t * const pred_cu,
-  const int x,
-  const int y,
-  const int depth,
-  const int width,
-  const int height,
   enum uvg_tree_type tree_type,
-  const color_t color)
+  const color_t color,
+  const cu_loc_t* const cu_loc)
 {
   
-  if (uvg_is_lfnst_allowed(state, pred_cu, width, height, x, y, tree_type, color, NULL)) {
+  if (uvg_is_lfnst_allowed(state, pred_cu, tree_type, color, cu_loc)) {
     // Getting separate tree bool from block size is a temporary fix until a proper dual tree check is possible (there is no dual tree structure at time of writing this).
     // VTM seems to force explicit dual tree structure for small 4x4 blocks
-    bool is_separate_tree = depth == 4 || tree_type != UVG_BOTH_T;
+    bool is_separate_tree = tree_type != UVG_BOTH_T;
 
     const int lfnst_index = !is_separate_tree || color == COLOR_Y ? pred_cu->lfnst_idx : pred_cu->cr_lfnst_idx;
     assert((lfnst_index >= 0 && lfnst_index < 3) && "Invalid LFNST index.");
@@ -1752,6 +1694,8 @@ void uvg_encode_coding_tree(
       uvg_encode_intra_luma_coding_unit(state, cabac, cur_cu, cu_loc, NULL, NULL);
     }
 
+    const bool is_local_dual_tree = cu_height * cu_width < 64 && tree_type == UVG_BOTH_T;
+
     // Code chroma prediction mode.
     if (state->encoder_control->chroma_format != UVG_CSP_400 && depth != 4 && tree_type == UVG_BOTH_T) {
       encode_chroma_intra_cu(cabac, cur_cu, state->encoder_control->cfg.cclm, NULL);
@@ -1779,7 +1723,7 @@ void uvg_encode_coding_tree(
     }
 
     if (tree_type != UVG_CHROMA_T) {
-      bool lfnst_written = encode_lfnst_idx(state, cabac, cur_cu, x, y, depth, cu_width, cu_height, tree_type, COLOR_Y);
+      bool lfnst_written = encode_lfnst_idx(state, cabac, cur_cu, is_local_dual_tree ? UVG_LUMA_T : tree_type, COLOR_Y, cu_loc);
     }
     encode_mts_idx(state, cabac, cur_cu, cu_loc);
 
@@ -1795,7 +1739,7 @@ void uvg_encode_coding_tree(
       tmp->lfnst_last_scan_pos = false;
       encode_transform_coeff(state, &cu_loc, depth, 0, 1, coeff, tree_type, true, false, &luma_cbf_ctx, cu_loc);
       // Write LFNST only once for single tree structure
-      encode_lfnst_idx(state, cabac, tmp, x, y, depth, cu_width, cu_height, tree_type, COLOR_UV);
+      encode_lfnst_idx(state, cabac, tmp, is_local_dual_tree ? UVG_CHROMA_T : tree_type, COLOR_UV, cu_loc);
     }
   }
 
diff --git a/src/encode_coding_tree.h b/src/encode_coding_tree.h
index e75ad46a..a7fe896b 100644
--- a/src/encode_coding_tree.h
+++ b/src/encode_coding_tree.h
@@ -45,13 +45,9 @@ bool uvg_is_mts_allowed(const encoder_state_t* const state, cu_info_t* const pre
 bool uvg_is_lfnst_allowed(
   const encoder_state_t* const state,
   const cu_info_t* const pred_cu,
-  const int width,
-  const int height,
-  const int x,
-  const int y,
   enum uvg_tree_type tree_type,
   const color_t color,
-  const lcu_t* lcu);
+  const cu_loc_t* const cu_loc);
 
 void uvg_encode_coding_tree(
   encoder_state_t * const state,
diff --git a/src/search.c b/src/search.c
index 883c9d59..51de64f0 100644
--- a/src/search.c
+++ b/src/search.c
@@ -673,8 +673,11 @@ static double cu_rd_cost_tr_split_accurate(
     }
   }
 
-  if(cu_loc->width == 4 || tree_type == UVG_LUMA_T) {
-    if (uvg_is_lfnst_allowed(state, tr_cu, width, height, cu_loc->local_x, cu_loc->local_y, tree_type, COLOR_Y, lcu)) {
+  const bool is_local_sep_tree = pred_cu->log2_width + pred_cu->log2_height < 6 && tree_type == UVG_BOTH_T;
+
+  if(is_local_sep_tree || tree_type == UVG_LUMA_T) {
+
+    if (uvg_is_lfnst_allowed(state, tr_cu, is_local_sep_tree ? UVG_LUMA_T : tree_type, COLOR_Y, cu_loc)) {
       const int lfnst_idx = tr_cu->lfnst_idx;
       CABAC_FBITS_UPDATE(
         cabac,
@@ -746,11 +749,12 @@ static double cu_rd_cost_tr_split_accurate(
     }
   }
 
-  if (uvg_is_lfnst_allowed(state, tr_cu, width, height, cu_loc->local_x, cu_loc->local_y, tree_type, cu_loc->width == 4 || tree_type == UVG_CHROMA_T ? COLOR_UV : COLOR_Y, lcu)) {
-    const int lfnst_idx = (cu_loc->width != 4 && tree_type != UVG_CHROMA_T) ? tr_cu->lfnst_idx : tr_cu->cr_lfnst_idx;
+  const bool is_chroma_tree = is_local_sep_tree || tree_type == UVG_CHROMA_T;
+  if (uvg_is_lfnst_allowed(state, tr_cu, is_local_sep_tree ? UVG_CHROMA_T : tree_type, is_chroma_tree ? COLOR_UV : COLOR_Y, cu_loc)) {
+    const int lfnst_idx = is_chroma_tree ? tr_cu->cr_lfnst_idx : tr_cu->lfnst_idx;
     CABAC_FBITS_UPDATE(
       cabac,
-      &cabac->ctx.lfnst_idx_model[tr_cu->depth == 4 || tree_type != UVG_BOTH_T],
+      &cabac->ctx.lfnst_idx_model[is_chroma_tree],
       lfnst_idx != 0,
       tr_tree_bits,
       "lfnst_idx");
@@ -971,6 +975,8 @@ static double search_cu(
   cur_cu->lfnst_idx = 0;
   cur_cu->joint_cb_cr = 0;
   cur_cu->split_tree = split_tree.split_tree;
+  cur_cu->log2_width = uvg_g_convert_to_log2[cu_width];
+  cur_cu->log2_height = uvg_g_convert_to_log2[cu_height];
 
   // If the CU is completely inside the frame at this depth, search for
   // prediction modes at this depth.
diff --git a/src/search_intra.c b/src/search_intra.c
index 2355fad1..e40df0df 100644
--- a/src/search_intra.c
+++ b/src/search_intra.c
@@ -300,7 +300,7 @@ static double search_intra_trdepth(
     pred_cu->tr_depth = depth;
 
     const bool mts_enabled = (state->encoder_control->cfg.mts == UVG_MTS_INTRA || state->encoder_control->cfg.mts == UVG_MTS_BOTH)
-      && tr_cu->depth == tr_cu->tr_depth;
+      && PU_IS_TU(pred_cu);
 
     nosplit_cost = 0.0;
 
@@ -330,10 +330,10 @@ static double search_intra_trdepth(
       num_transforms = pred_cu->intra.isp_mode == ISP_MODE_NO_ISP ? num_transforms : 1;
     }
     const int mts_start = trafo;
-    //TODO: height
-    if (state->encoder_control->cfg.trskip_enable && 
-        width <= (1 << state->encoder_control->cfg.trskip_max_size) /*&& height == 4*/ && 
-        pred_cu->intra.isp_mode == ISP_MODE_NO_ISP) { // tr_skip cannot be used wit ISP
+    if (state->encoder_control->cfg.trskip_enable 
+      && width <= (1 << state->encoder_control->cfg.trskip_max_size)
+      && height <= (1 << state->encoder_control->cfg.trskip_max_size)
+      && pred_cu->intra.isp_mode == ISP_MODE_NO_ISP) {
       num_transforms = MAX(num_transforms, 2);
     }
     pred_cu->intra.mode_chroma = -1;
@@ -346,9 +346,10 @@ static double search_intra_trdepth(
       max_lfnst_idx = 0;
     }
 
+    const bool is_local_dual_tree = pred_cu->log2_width + pred_cu->log2_height < 6 && tree_type == UVG_BOTH_T;
+
     int start_idx = 0;
-    int end_idx = state->encoder_control->cfg.lfnst && 
-                  depth == pred_cu->tr_depth &&
+    int end_idx = state->encoder_control->cfg.lfnst && PU_IS_TU(pred_cu) &&
                   uvg_can_use_isp_with_lfnst(width, height, pred_cu->intra.isp_mode, tree_type) ? max_lfnst_idx : 0;
     for (int i = start_idx; i < end_idx + 1; ++i) {
       search_data->lfnst_costs[i] = MAX_DOUBLE;
@@ -436,11 +437,11 @@ static double search_intra_trdepth(
           lcu,
           search_data->best_isp_cbfs);
         double transform_bits = 0;
-        if (state->encoder_control->cfg.lfnst && depth == pred_cu->tr_depth &&
+        if (state->encoder_control->cfg.lfnst && PU_IS_TU(pred_cu) &&
             trafo != MTS_SKIP) {
           if (!constraints[0] && constraints[1]) {
             transform_bits += CTX_ENTROPY_FBITS(
-              &state->search_cabac.ctx.lfnst_idx_model[tr_cu->depth == 4 ||
+              &state->search_cabac.ctx.lfnst_idx_model[is_local_dual_tree ||
                 tree_type == UVG_LUMA_T],
               lfnst_idx != 0);
             if (lfnst_idx > 0) {
@@ -566,30 +567,6 @@ static double search_intra_trdepth(
     }
 
     nosplit_cbf = pred_cu->cbf;
-
-    uvg_pixels_blit(
-      lcu->rec.y,
-      nosplit_pixels.y,
-      width,
-      width,
-      LCU_WIDTH,
-      width);
-    if (reconstruct_chroma) {
-      uvg_pixels_blit(
-        lcu->rec.u,
-        nosplit_pixels.u,
-        width_c,
-        width_c,
-        LCU_WIDTH_C,
-        width_c);
-      uvg_pixels_blit(
-        lcu->rec.v,
-        nosplit_pixels.v,
-        width_c,
-        width_c,
-        LCU_WIDTH_C,
-        width_c);
-    }
   }
     
   
@@ -619,31 +596,7 @@ static double search_intra_trdepth(
       uvg_cu_loc_ctor(&split_cu_loc, cu_loc->x + half_width, cu_loc->y + half_height, half_width, half_height);
       split_cost += search_intra_trdepth(state, &split_cu_loc, max_depth, nosplit_cost, search_data, lcu, tree_type);
     }
-
-    double cbf_bits = 0.0;
-
-    // Add cost of cbf chroma bits on transform tree.
-    // All cbf bits are accumulated to pred_cu.cbf and cbf_is_set returns true
-    // if cbf is set at any level >= depth, so cbf chroma is assumed to be 0
-    // if this and any previous transform block has no chroma coefficients.
-    // When searching the first block we don't actually know the real values,
-    // so this will code cbf as 0 and not code the cbf at all for descendants.
-    if (state->encoder_control->chroma_format != UVG_CSP_400) {
-      const uint8_t tr_depth = depth - pred_cu->depth;
-      cabac_data_t* cabac = (cabac_data_t *)&state->search_cabac;
-
-      cabac_ctx_t* ctx = &(cabac->ctx.qt_cbf_model_cb[0]);
-      if (tr_depth == 0 || cbf_is_set(pred_cu->cbf, depth - 1, COLOR_U)) {
-        CABAC_FBITS_UPDATE(cabac, ctx, cbf_is_set(pred_cu->cbf, depth, COLOR_U), cbf_bits, "cbf_cb");
-      }
-      ctx = &(state->cabac.ctx.qt_cbf_model_cr[cbf_is_set(pred_cu->cbf, depth, COLOR_U)]);
-      if (tr_depth == 0 || cbf_is_set(pred_cu->cbf, depth - 1, COLOR_V)) {
-        CABAC_FBITS_UPDATE(cabac, ctx, cbf_is_set(pred_cu->cbf, depth, COLOR_V), cbf_bits, "cbf_cr");
-      }
-    }
-
-    double bits = cbf_bits;
-    split_cost += bits * state->lambda;
+    
   } else {
     assert(width <= TR_MAX_WIDTH);
   }
@@ -652,17 +605,6 @@ static double search_intra_trdepth(
     return split_cost;
   } else {
     uvg_lcu_fill_trdepth(lcu, cu_loc, depth, tree_type);
-
-    pred_cu->cbf = nosplit_cbf;
-
-    // We only restore the pixel data and not coefficients or cbf data.
-    // The only thing we really need are the border pixels.uvg_intra_get_dir_luma_predictor
-    uvg_pixels_blit(nosplit_pixels.y, lcu->rec.y, width, width, width, LCU_WIDTH);
-    if (reconstruct_chroma) {
-      uvg_pixels_blit(nosplit_pixels.u, lcu->rec.u, width_c, width_c, width_c, LCU_WIDTH_C);
-      uvg_pixels_blit(nosplit_pixels.v, lcu->rec.v, width_c, width_c, width_c, LCU_WIDTH_C);
-    }
-
     return nosplit_cost;
   }
 }
diff --git a/src/transform.c b/src/transform.c
index 86ff515b..2a532715 100644
--- a/src/transform.c
+++ b/src/transform.c
@@ -723,7 +723,7 @@ void uvg_chroma_transform_search(
         COEFF_ORDER_LINEAR);
     }
     if((depth == 4 || tree_type == UVG_CHROMA_T) && state->encoder_control->cfg.lfnst && 0) {
-      if(uvg_is_lfnst_allowed(state, pred_cu, width, height, 0, 0 , UVG_CHROMA_T, COLOR_UV, lcu)) {
+      if(uvg_is_lfnst_allowed(state, pred_cu, UVG_CHROMA_T, COLOR_UV, cu_loc)) {
         const int lfnst_idx = pred_cu->cr_lfnst_idx;
         CABAC_FBITS_UPDATE(
           &state->search_cabac,