diff --git a/flow/designs/ihp-sg13g2/aes/config.mk b/flow/designs/ihp-sg13g2/aes/config.mk
index 64c4b4b547..7f89a11557 100644
--- a/flow/designs/ihp-sg13g2/aes/config.mk
+++ b/flow/designs/ihp-sg13g2/aes/config.mk
@@ -13,6 +13,4 @@ export TNS_END_PERCENT = 100
 
 export USE_FILL = 1
 
-export REMOVE_ABC_BUFFERS = 1
-
 export SYNTH_USE_SYN = 1
diff --git a/flow/designs/sky130hd/riscv32i/config.mk b/flow/designs/sky130hd/riscv32i/config.mk
index d9e25b7fdf..3b1c3d064b 100644
--- a/flow/designs/sky130hd/riscv32i/config.mk
+++ b/flow/designs/sky130hd/riscv32i/config.mk
@@ -8,8 +8,6 @@ export SDC_FILE      = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/constraint.
 export CORE_UTILIZATION = 45
 export PLACE_DENSITY_LB_ADDON = 0.2
 
-export REMOVE_ABC_BUFFERS = 1
-
 #export SWAP_ARITH_OPERATORS = 1
 #export OPENROAD_HIERARCHICAL = 1
 
diff --git a/flow/designs/sky130hs/riscv32i/config.mk b/flow/designs/sky130hs/riscv32i/config.mk
index 411ba6b86c..232ab3fbed 100644
--- a/flow/designs/sky130hs/riscv32i/config.mk
+++ b/flow/designs/sky130hs/riscv32i/config.mk
@@ -13,8 +13,6 @@ export TNS_END_PERCENT = 100
 
 export FASTROUTE_TCL = $(DESIGN_HOME)/$(PLATFORM)/$(DESIGN_NICKNAME)/fastroute.tcl
 
-export REMOVE_ABC_BUFFERS = 1
-
 export SWAP_ARITH_OPERATORS = 1
 export OPENROAD_HIERARCHICAL = 1