diff --git a/ports/raspberrypi/Makefile b/ports/raspberrypi/Makefile
index 967bd67078..840b723398 100644
--- a/ports/raspberrypi/Makefile
+++ b/ports/raspberrypi/Makefile
@@ -260,6 +260,12 @@ $(BUILD)/stage2.c: stage2.c.jinja gen_stage2.py | $(BUILD)/
 	$(STEPECHO) "GEN $<"
 	$(Q)$(PYTHON3) gen_stage2.py $< $@ $(EXTERNAL_FLASH_DEVICES)
 
+$(HEADER_BUILD)/flash_info.h: flash_info.h.jinja gen_stage2.py | $(HEADER_BUILD)/
+	$(STEPECHO) "GEN $<"
+	$(Q)$(PYTHON3) gen_stage2.py $< $@ $(EXTERNAL_FLASH_DEVICES)
+
+$(BUILD)/supervisor/internal_flash.o: $(HEADER_BUILD)/flash_info.h
+
 $(BUILD)/boot2.elf: $(BUILD)/stage2.c
 	$(STEPECHO) "BOOT $<"
 	$(Q)$(CC) $(CFLAGS) $(BOOT2_S_CFLAGS) -Os -ggdb3 -I. -fPIC --specs=nosys.specs -nostartfiles -Wl,-T,boot_stage2.ld  -Wl,-Map=$@.map -o $@ $<
diff --git a/ports/raspberrypi/flash_info.h.jinja b/ports/raspberrypi/flash_info.h.jinja
new file mode 100644
index 0000000000..cfeb4840b9
--- /dev/null
+++ b/ports/raspberrypi/flash_info.h.jinja
@@ -0,0 +1,5 @@
+// This file is auto-generated using gen_stage2.py
+
+#pragma once
+
+#define FLASH_DEFAULT_POWER_OF_TWO {{ default_power_of_two }}
diff --git a/ports/raspberrypi/gen_stage2.py b/ports/raspberrypi/gen_stage2.py
index 4a67905183..759384e17f 100644
--- a/ports/raspberrypi/gen_stage2.py
+++ b/ports/raspberrypi/gen_stage2.py
@@ -1,3 +1,4 @@
+import math
 import sys
 import cascadetoml
 import pathlib
@@ -46,6 +47,18 @@ def main(input_template: pathlib.Path, output_path: pathlib.Path, skus: str = ty
 
     max_clock_speed_mhz = min((x.get("max_clock_speed_mhz", 1000) for x in flashes["nvm"]))
 
+    default_power_of_two = None
+    for nvm in flashes["nvm"]:
+        capacity = nvm.get("capacity", 0)
+        if not 21 <= capacity < 30:
+            power_of_two = int(math.log2(nvm["total_size"]))
+            if not default_power_of_two:
+                default_power_of_two = power_of_two
+            else:
+                default_power_of_two = min(power_of_two, default_power_of_two)
+    if not default_power_of_two:
+        default_power_of_two = 21
+
     # Check that we have a consistent way to set quad enable.
     if continuous_status_write is None and split_status_write is None:
         print("quad not ok", continuous_status_write, split_status_write)
@@ -71,6 +84,7 @@ def main(input_template: pathlib.Path, output_path: pathlib.Path, skus: str = ty
         "clock_divider": clock_divider,
         "read_command": read_command,
         "wait_cycles": wait_cycles,
+        "default_power_of_two": default_power_of_two,
     }
 
     template = Template(input_template.read_text())
diff --git a/ports/raspberrypi/supervisor/internal_flash.c b/ports/raspberrypi/supervisor/internal_flash.c
index 51068e184a..fa18f24fe0 100644
--- a/ports/raspberrypi/supervisor/internal_flash.c
+++ b/ports/raspberrypi/supervisor/internal_flash.c
@@ -32,6 +32,7 @@
 
 #include "extmod/vfs.h"
 #include "extmod/vfs_fat.h"
+#include "genhdr/flash_info.h"
 #include "py/mphal.h"
 #include "py/obj.h"
 #include "py/runtime.h"
@@ -68,7 +69,7 @@ void supervisor_flash_init(void) {
     uint8_t cmd[] = {0x9f, 0, 0, 0};
     uint8_t data[4];
     flash_do_cmd(cmd, data, 4);
-    uint8_t power_of_two = 21;
+    uint8_t power_of_two = FLASH_DEFAULT_POWER_OF_TWO;
     // Flash must be at least 2MB (1 << 21) because we use the first 1MB for the
     // CircuitPython core. We validate the range because Adesto Tech flash chips
     // don't return the correct value. So, we default to 2MB which will work for