diff --git a/examples/wch/ch32v307-make-baremetal-builtin/Makefile b/examples/wch/ch32v307-make-baremetal-builtin/Makefile
index d00418d5..3e52679a 100644
--- a/examples/wch/ch32v307-make-baremetal-builtin/Makefile
+++ b/examples/wch/ch32v307-make-baremetal-builtin/Makefile
@@ -1,3 +1,7 @@
+# By default, this firmware is built with 288/32 flash/ram device configuration
+# To build it with 256/64 configuration, run the following:
+# make CFLAGS_EXTRA="-Wl,--defsym -Wl,RAM_64K=1"
+
 ROOT ?= $(realpath $(PWD)/../../..)
 PREFIX ?= riscv-none-elf
 #PREFIX ?= docker run --platform linux/amd64 --rm -it -v$(ROOT):$(ROOT) -w $(PWD) mdashnet/riscv riscv-none-elf
@@ -5,7 +9,7 @@ CFLAGS = -W -Wall -Wextra -Wundef -Wshadow -Wdouble-promotion
 CFLAGS += -Wformat-truncation -Wconversion -Wno-sign-conversion
 CFLAGS += -ffunction-sections -fdata-sections -fno-common
 CFLAGS += -DSYSCLK_FREQ_144MHz_HSE -I. -Ivendor -g3 -Os
-CFLAGS += -march=rv32imafc -mabi=ilp32 $(CFLAGS_EXTRA)
+CFLAGS += -march=rv32imafc -mabi=ilp32
 LDFLAGS = -T vendor/link.ld -nostartfiles --specs=nano.specs --specs=nosys.specs -Wl,--gc-sections
 SOURCES = hal.c main.c mongoose.c net.c packed_fs.c
 SOURCES += vendor/system_ch32v30x.c vendor/startup_ch32v30x_D8C.S
@@ -24,7 +28,7 @@ firmware.bin: firmware.elf
 	$(PREFIX)-size --format=berkeley $<
 
 firmware.elf: $(SOURCES) hal.h mongoose_custom.h Makefile
-	$(PREFIX)-gcc $(SOURCES) $(CFLAGS) $(LDFLAGS) -o $@
+	$(PREFIX)-gcc $(SOURCES) $(CFLAGS) $(LDFLAGS) $(CFLAGS_EXTRA) -o $@
 
 flash: firmware.bin
 	wchisp flash $<
diff --git a/examples/wch/ch32v307-make-baremetal-builtin/vendor/link.ld b/examples/wch/ch32v307-make-baremetal-builtin/vendor/link.ld
index 0035ba44..b100d630 100644
--- a/examples/wch/ch32v307-make-baremetal-builtin/vendor/link.ld
+++ b/examples/wch/ch32v307-make-baremetal-builtin/vendor/link.ld
@@ -3,9 +3,13 @@ __stack_size = 4096;
 PROVIDE( _stack_size = __stack_size );
 
 MEMORY {
-  /*  Possible configurations: 192/128, 224/96, 256/64, 288/32 */
-  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = 288k
-  RAM (xrw) : ORIGIN = 0x20000000, LENGTH = 32k
+  /* 
+   * Possible configurations: 192/128, 224/96, 256/64, 288/32
+   * By default, we're building with 288/32 configuration
+   * To build with 256/64, add -Wl,--defsym=RAM_64K=1
+   */
+  FLASH (rx) : ORIGIN = 0x00000000, LENGTH = DEFINED(RAM_64K) ? 256k : 288k
+  RAM (xrw) : ORIGIN = 0x20000000, LENGTH = DEFINED(RAM_64K) ? 64k : 32k
 }
 
 SECTIONS {