diff --git a/cores/rp2040/Bootsel.cpp b/cores/rp2040/Bootsel.cpp
index 63a2717..a9e5959 100644
--- a/cores/rp2040/Bootsel.cpp
+++ b/cores/rp2040/Bootsel.cpp
@@ -26,7 +26,8 @@ static bool __no_inline_not_in_flash_func(get_bootsel_button)() {
 
     // Must disable interrupts, as interrupt handlers may be in flash, and we
     // are about to temporarily disable flash access!
-    uint32_t flags = save_and_disable_interrupts();
+    noInterrupts();
+    rp2040.idleOtherCore();
 
     // Set chip select to Hi-Z
     hw_write_masked(&ioqspi_hw->io[CS_PIN_INDEX].ctrl,
@@ -46,7 +47,8 @@ static bool __no_inline_not_in_flash_func(get_bootsel_button)() {
                     GPIO_OVERRIDE_NORMAL << IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_LSB,
                     IO_QSPI_GPIO_QSPI_SS_CTRL_OEOVER_BITS);
 
-    restore_interrupts(flags);
+    interrupts();
+    rp2040.resumeOtherCore();
 
     return button_state;
 }
diff --git a/cores/rp2040/RP2040.h b/cores/rp2040/RP2040.h
index a958777..3d79338 100644
--- a/cores/rp2040/RP2040.h
+++ b/cores/rp2040/RP2040.h
@@ -23,6 +23,7 @@
 #include <hardware/pio.h>
 #include <pico/multicore.h>
 #include <pico/util/queue.h>
+#include <CoreMutex.h>
 
 class _MFIFO {
 public:
@@ -132,7 +133,6 @@ public:
 extern RP2040 rp2040;
 
 // Wrapper class for PIO programs, abstracting common operations out
-// TODO - Make dualcore safe
 // TODO - Add unload/destructor
 class PIOProgram {
 public:
@@ -140,6 +140,8 @@ public:
 
     // Possibly load into a PIO and allocate a SM
     bool prepare(PIO *pio, int *sm, int *offset) {
+        extern mutex_t _pioMutex;
+        CoreMutex m(&_pioMutex);
         // Is there an open slot to run in, first?
         if (!_findFreeSM(pio, sm)) return false;
 	// Is it loaded on that PIO?
diff --git a/cores/rp2040/main.cpp b/cores/rp2040/main.cpp
index 4b34dab..27fd1a2 100644
--- a/cores/rp2040/main.cpp
+++ b/cores/rp2040/main.cpp
@@ -26,6 +26,9 @@ RP2040 rp2040;
 
 volatile bool _MFIFO::_otherIdled = false;
 
+auto_init_mutex(_pioMutex);
+
+
 extern void setup();
 extern void loop();