diff --git a/tools/make/diamond_preamble.mak b/tools/make/diamond_preamble.mak
index 86aaf2f..24b0fe2 100644
--- a/tools/make/diamond_preamble.mak
+++ b/tools/make/diamond_preamble.mak
@@ -23,12 +23,12 @@ endif
 TOOLS_DIR  = $(BASE_DIR)/../tools
 LIB_DIR    = $(BASE_DIR)/../lib
 
-O ?= .
+BUILD_BASE_DIR ?= .
 
 ifdef NAME
-BUILD_DIR = $(abspath $(O)/build-$(NAME))
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build-$(NAME))
 else
-BUILD_DIR = $(abspath $(O)/build)
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build)
 endif
 
 IP_BUILD_DIR = $(abspath ./build-ip/$(subst /,,$(PART_ID)))
diff --git a/tools/make/quartus_preamble.mak b/tools/make/quartus_preamble.mak
index 2fe20e5..d577227 100644
--- a/tools/make/quartus_preamble.mak
+++ b/tools/make/quartus_preamble.mak
@@ -23,12 +23,12 @@ endif
 TOOLS_DIR  = $(BASE_DIR)/../tools
 LIB_DIR    = $(BASE_DIR)/../lib
 
-O ?= .
+BUILD_BASE_DIR ?= .
 
 ifdef NAME
-BUILD_DIR = $(abspath $(O)/build-$(NAME))
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build-$(NAME))
 else
-BUILD_DIR = $(abspath $(O)/build)
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build)
 endif
 
 IP_BUILD_DIR = $(abspath ./build-ip/$(subst /,,$(PART_ID)))
diff --git a/tools/make/viv_preamble.mak b/tools/make/viv_preamble.mak
index ab9e017..df0f271 100644
--- a/tools/make/viv_preamble.mak
+++ b/tools/make/viv_preamble.mak
@@ -24,12 +24,12 @@ SIMLIB_DIR = $(abspath $(BASE_DIR)/../sim)
 LIB_IP_DIR = $(abspath $(LIB_DIR)/ip)
 HLS_IP_DIR = $(abspath $(LIB_DIR)/hls)
 
-O ?= .
+BUILD_BASE_DIR ?= .
 
 ifdef NAME
-BUILD_DIR = $(abspath $(O)/build-$(NAME))
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build-$(NAME))
 else
-BUILD_DIR = $(abspath $(O)/build)
+BUILD_DIR = $(abspath $(BUILD_BASE_DIR)/build)
 endif
 
 IP_BUILD_DIR = $(abspath ./build-ip/$(subst /,,$(PART_ID)))
diff --git a/top/e31x/Makefile b/top/e31x/Makefile
index 45b8dae..8c0e32b 100644
--- a/top/e31x/Makefile
+++ b/top/e31x/Makefile
@@ -14,6 +14,9 @@
 ## build/usrp_<product>_fpga_<image_type>.dts:    Device tree source file
 ## build/usrp_<product>_fpga_<image_type>.rpt:    Build report (includes utilization and timing summary)
 
+# Base output directory for all builds
+BUILD_BASE_DIR ?= .
+
 # Initialize a build seed. This can be changed to randomly affect build results.
 BUILD_SEED ?= 0
 DEFS += BUILD_SEED=$(BUILD_SEED)
@@ -42,9 +45,9 @@ ifeq ($(TARGET),bin)
 	post_build = @\
 		mkdir -p build; \
 		echo "Exporting bitstream file..."; \
-		cp build-$(1)/e31x.bit build/usrp_`echo $(2) | tr A-Z a-z`_fpga.bit; \
+		cp $(BUILD_BASE_DIR)/build-$(1)/e31x.bit build/usrp_`echo $(2) | tr A-Z a-z`_fpga.bit; \
 		echo "Exporting build report..."; \
-		cp build-$(1)/build.rpt build/usrp_`echo $(2) | tr A-Z a-z`_fpga.rpt; \
+		cp $(BUILD_BASE_DIR)/build-$(1)/build.rpt build/usrp_`echo $(2) | tr A-Z a-z`_fpga.rpt; \
 		echo "Build DONE ... $(1)";
 else
 	post_build = @echo "Skipping bitfile export."
diff --git a/top/e320/Makefile b/top/e320/Makefile
index ec555a4..e2e6e8a 100644
--- a/top/e320/Makefile
+++ b/top/e320/Makefile
@@ -14,6 +14,9 @@
 ## build/usrp_<product>_fpga_<image_type>.dts:    Device tree source file
 ## build/usrp_<product>_fpga_<image_type>.rpt:    Build report (includes utilization and timing summary)
 
+# Base output directory for all builds
+BUILD_BASE_DIR ?= .
+
 # Initialize a build seed. This can be changed to randomly affect build results.
 BUILD_SEED ?= 0
 
@@ -45,9 +48,9 @@ ifeq ($(TARGET),bin)
 	post_build = @\
 		mkdir -p build; \
 		echo "Exporting bitstream file..."; \
-		cp build-$(1)_$(2)/e320.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/e320.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
 		echo "Exporting build report..."; \
-		cp build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
 		echo "Build DONE ... $(1)_$(2)";
 else
 	post_build = @echo "Skipping bitfile export."
diff --git a/top/n3xx/Makefile b/top/n3xx/Makefile
index 1041545..5abafb3 100644
--- a/top/n3xx/Makefile
+++ b/top/n3xx/Makefile
@@ -23,6 +23,9 @@
 # Uncomment this line to add four example Aurora loopback lanes on the QSFP NPIO bus.
 # OPTIONS += QSFP_LANES=4
 
+# Base output directory for all builds
+BUILD_BASE_DIR ?= .
+
 # Initialize a build seed. This can be changed to randomly affect build results.
 BUILD_SEED ?= 0
 
@@ -68,9 +71,9 @@ ifeq ($(TARGET),bin)
 	post_build = @\
 		mkdir -p build; \
 		echo "Exporting bitstream file..."; \
-		cp build-$(1)_$(2)/n3xx.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/n3xx.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
 		echo "Exporting build report..."; \
-		cp build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
 		echo "Build DONE ... $(1)_$(2)";
 else
 	post_build = @echo "Skipping bitfile export."
diff --git a/top/x300/Makefile b/top/x300/Makefile
index 10f347e..313dc7e 100644
--- a/top/x300/Makefile
+++ b/top/x300/Makefile
@@ -21,6 +21,9 @@
 
 CREATE_LVBITX=python ../../lib/io_port2/create-lvbitx.py
 
+# Base output directory for all builds
+BUILD_BASE_DIR ?= .
+
 # Initialize a build seed. This can be changed to randomly affect build results.
 BUILD_SEED ?= 0
 
@@ -56,13 +59,13 @@ ifeq ($(TARGET),bin)
 	post_build = @\
 		mkdir -p build; \
 		echo "Exporting bitstream files..."; \
-		cp build-$(1)_$(2)/x300.bin build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bin; \
-		cp build-$(1)_$(2)/x300.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/x300.bin build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bin; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/x300.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
 		echo "Generating LVBITX..."; \
-		$(CREATE_LVBITX) --input-bin=build-$(1)_$(2)/x300.bin --output-lvbitx=build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).lvbitx --device="USRP $(1)" x3x0_base.lvbitx; \
+		$(CREATE_LVBITX) --input-bin=$(BUILD_BASE_DIR)/build-$(1)_$(2)/x300.bin --output-lvbitx=build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).lvbitx --device="USRP $(1)" x3x0_base.lvbitx; \
 		cp -f x3x0_base.lvbitx build/`echo $(1) | tr A-Z a-z`.lvbitx_base; \
 		echo "Exporting build report..."; \
-		cp build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
 		echo "Build DONE ... $(1)_$(2)";
 else
 	post_build = @echo "Skipping bitfile export."
diff --git a/top/x400/Makefile b/top/x400/Makefile
index 6b3a078..9d458e7 100644
--- a/top/x400/Makefile
+++ b/top/x400/Makefile
@@ -16,7 +16,8 @@
 ##  build/usrp_<product>_fpga_<image_type>.dts:  Device tree source file
 ##  build/usrp_<product>_fpga_<image_type>.rpt:  Build report (includes utilization and timing summary)
 
-
+# Base output directory for all builds
+BUILD_BASE_DIR ?= .
 
 # Definitions
 # MGT Types from x4xx_mgt_type.vh
@@ -97,9 +98,9 @@ ifeq ($(TARGET),bin)
 	post_build = @\
 		mkdir -p build; \
 		echo "Exporting bitstream file..."; \
-		cp build-$(1)_$(2)/x4xx.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/x4xx.bit build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).bit; \
 		echo "Exporting build report..."; \
-		cp build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
+		cp $(BUILD_BASE_DIR)/build-$(1)_$(2)/build.rpt build/usrp_`echo $(1) | tr A-Z a-z`_fpga_$(2).rpt; \
 		echo "Build DONE ... $(1)_$(2)";
 else
 	post_build = @echo "Skipping bitfile export."