diff --git a/rp2040-hal/src/rom_data.rs b/rp2040-hal/src/rom_data.rs
index 4bfea7a..9f46297 100644
--- a/rp2040-hal/src/rom_data.rs
+++ b/rp2040-hal/src/rom_data.rs
@@ -91,7 +91,7 @@ rom_funcs! {
     /// Program data to a range of flash addresses starting at addr (offset from the start of flash)
     /// and count bytesin size. addr must be aligned to a 256-byte boundary, and count must be a
     /// multiple of 256.
-    b"RP" flash_range_program(addr: u32, data: *mut u8, count: usize) -> ();
+    b"RP" flash_range_program(addr: u32, data: *const u8, count: usize) -> ();
 
     /// Flush and enable the XIP cache. Also clears the IO forcing on QSPI CSn, so that the SSI can
     /// drive the flashchip select as normal.