diff --git a/src/rp2040/hardware_regs/include/hardware/platform_defs.h b/src/rp2040/hardware_regs/include/hardware/platform_defs.h
index f3193da..08c7159 100644
--- a/src/rp2040/hardware_regs/include/hardware/platform_defs.h
+++ b/src/rp2040/hardware_regs/include/hardware/platform_defs.h
@@ -36,7 +36,10 @@
 
 #define PIO_INSTRUCTION_COUNT _u(32)
 
+// PICO_CONFIG: XOSC_MHZ, The crystal oscillator frequency in Mhz, type=int, default=12, advanced=true, group=hardware_base
+#ifndef XOSC_MHZ
 #define XOSC_MHZ _u(12)
+#endif
 
 #endif
 
diff --git a/src/rp2_common/hardware_xosc/xosc.c b/src/rp2_common/hardware_xosc/xosc.c
index 9a95e37..7a7055c 100644
--- a/src/rp2_common/hardware_xosc/xosc.c
+++ b/src/rp2_common/hardware_xosc/xosc.c
@@ -13,8 +13,8 @@
 #include "hardware/regs/xosc.h"
 #include "hardware/xosc.h"
 
-#if XOSC_MHZ < 1 || XOSC_MHZ > 15
-#error XOSC_MHZ must be in the range 1-15
+#if XOSC_MHZ < 1 || XOSC_MHZ > 50
+#error XOSC_MHZ must be in the range 1-50
 #endif
 
 #define STARTUP_DELAY (((((XOSC_MHZ * MHZ) / 1000) + 128) / 256) * PICO_XOSC_STARTUP_DELAY_MULTIPLIER)