diff --git a/MODULE.bazel b/MODULE.bazel
index 31d6105cc..111ed24cd 100644
--- a/MODULE.bazel
+++ b/MODULE.bazel
@@ -1,6 +1,6 @@
 module(
     name = "pico-sdk",
-    version = "2.2.0",
+    version = "2.2.1-develop",
 )
 
 bazel_dep(name = "platforms", version = "0.0.9")
diff --git a/pico_sdk_version.cmake b/pico_sdk_version.cmake
index 0a3525873..aca3c585e 100644
--- a/pico_sdk_version.cmake
+++ b/pico_sdk_version.cmake
@@ -7,10 +7,10 @@ if (NOT DEFINED PICO_SDK_VERSION_MAJOR)
     set(PICO_SDK_VERSION_MINOR 2)
     # PICO_BUILD_DEFINE: PICO_SDK_VERSION_REVISION, SDK version revision, type=int, default=Current SDK revision, group=pico_base
     # PICO_CMAKE_CONFIG: PICO_SDK_VERSION_REVISION, SDK version revision, type=int, default=Current SDK revision, group=pico_base
-    set(PICO_SDK_VERSION_REVISION 0)
+    set(PICO_SDK_VERSION_REVISION 1)
     # PICO_BUILD_DEFINE: PICO_SDK_VERSION_PRE_RELEASE_ID, Optional SDK pre-release version identifier, default=Current SDK pre-release identifier, type=string, group=pico_base
     # PICO_CMAKE_CONFIG: PICO_SDK_VERSION_PRE_RELEASE_ID, Optional SDK pre-release version identifier, default=Current SDK pre-release identifier, type=string, group=pico_base
-    #set(PICO_SDK_VERSION_PRE_RELEASE_ID develop)
+    set(PICO_SDK_VERSION_PRE_RELEASE_ID develop)
 endif()
 
 # PICO_BUILD_DEFINE: PICO_SDK_VERSION_STRING, SDK version string, type=string, default=Current SDK version string, group=pico_base
diff --git a/src/boards/include/boards/waveshare_pico_cam_a.h b/src/boards/include/boards/waveshare_pico_cam_a.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_ble.h b/src/boards/include/boards/waveshare_rp2040_ble.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_eth.h b/src/boards/include/boards/waveshare_rp2040_eth.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_geek.h b/src/boards/include/boards/waveshare_rp2040_geek.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_matrix.h b/src/boards/include/boards/waveshare_rp2040_matrix.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_pizero.h b/src/boards/include/boards/waveshare_rp2040_pizero.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_power_management_hat_b.h b/src/boards/include/boards/waveshare_rp2040_power_management_hat_b.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_tiny.h b/src/boards/include/boards/waveshare_rp2040_tiny.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2040_touch_lcd_1.28.h b/src/boards/include/boards/waveshare_rp2040_touch_lcd_1.28.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_eth.h b/src/boards/include/boards/waveshare_rp2350_eth.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_geek.h b/src/boards/include/boards/waveshare_rp2350_geek.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_lcd_0.96.h b/src/boards/include/boards/waveshare_rp2350_lcd_0.96.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_lcd_1.28.h b/src/boards/include/boards/waveshare_rp2350_lcd_1.28.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_one.h b/src/boards/include/boards/waveshare_rp2350_one.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_plus_16mb.h b/src/boards/include/boards/waveshare_rp2350_plus_16mb.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_plus_4mb.h b/src/boards/include/boards/waveshare_rp2350_plus_4mb.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_tiny.h b/src/boards/include/boards/waveshare_rp2350_tiny.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_touch_lcd_1.28.h b/src/boards/include/boards/waveshare_rp2350_touch_lcd_1.28.h
old mode 100755
new mode 100644
diff --git a/src/boards/include/boards/waveshare_rp2350_zero.h b/src/boards/include/boards/waveshare_rp2350_zero.h
old mode 100755
new mode 100644
diff --git a/src/host/hardware_sync/include/hardware/sync.h b/src/host/hardware_sync/include/hardware/sync.h
index ae3865ae2..065cb3e52 100644
--- a/src/host/hardware_sync/include/hardware/sync.h
+++ b/src/host/hardware_sync/include/hardware/sync.h
@@ -109,8 +109,6 @@ extern "C" {
 
 void __sev();
 
-void __wev();
-
 void __wfi();
 
 void __wfe();
diff --git a/src/host/hardware_sync/sync_core0_only.c b/src/host/hardware_sync/sync_core0_only.c
index 70964c4b0..2578f0413 100644
--- a/src/host/hardware_sync/sync_core0_only.c
+++ b/src/host/hardware_sync/sync_core0_only.c
@@ -93,23 +93,44 @@ void PICO_WEAK_FUNCTION_IMPL_NAME(spin_unlock)(spin_lock_t *lock, uint32_t saved
     spin_unlock_unsafe(lock);
 }
 
-PICO_WEAK_FUNCTION_DEF(__sev)
+// These are defined on ARM hosts, but don't do what we want for the host
+// since this is a simulated build.
+
+#if PICO_C_COMPILER_IS_GNU || !__has_builtin(__sev)
+#define __sev_c __sev
+#else
+#pragma redefine_extname __sev_c __sev
+#endif
+
+#if PICO_C_COMPILER_IS_GNU || !__has_builtin(__wfi)
+#define __wfi_c __wfi
+#else
+#pragma redefine_extname __wfi_c __wfi
+#endif
+
+#if PICO_C_COMPILER_IS_GNU || !__has_builtin(__wfe)
+#define __wfe_c __wfe
+#else
+#pragma redefine_extname __wfe_c __wfe
+#endif
+
+PICO_WEAK_FUNCTION_DEF(__sev_c)
 
 volatile bool event_fired;
 
-void PICO_WEAK_FUNCTION_IMPL_NAME(__sev)() {
+void PICO_WEAK_FUNCTION_IMPL_NAME(__sev_c)() {
     event_fired = true;
 }
 
-PICO_WEAK_FUNCTION_DEF(__wfi)
+PICO_WEAK_FUNCTION_DEF(__wfi_c)
 
-void PICO_WEAK_FUNCTION_IMPL_NAME(__wfi)() {
+void PICO_WEAK_FUNCTION_IMPL_NAME(__wfi_c)() {
     panic("Can't wait on irq for host core0 only implementation");
 }
 
-PICO_WEAK_FUNCTION_DEF(__wfe)
+PICO_WEAK_FUNCTION_DEF(__wfe_c)
 
-void PICO_WEAK_FUNCTION_IMPL_NAME(__wfe)() {
+void PICO_WEAK_FUNCTION_IMPL_NAME(__wfe_c)() {
     while (!event_fired) tight_loop_contents();
 }
 
@@ -146,4 +167,4 @@ int PICO_WEAK_FUNCTION_IMPL_NAME(spin_lock_claim_unused)(bool required) {
 PICO_WEAK_FUNCTION_DEF(spin_lock_num)
 uint PICO_WEAK_FUNCTION_IMPL_NAME(spin_lock_num)(spin_lock_t *lock) {
     return 0;
-}
\ No newline at end of file
+}
diff --git a/src/rp2350/README.md b/src/rp2350/README.md
index 7a710171d..528d1932e 100644
--- a/src/rp2350/README.md
+++ b/src/rp2350/README.md
@@ -1,5 +1,5 @@
 This directory contains files specific to the RP2350 hardware. It is only used when building for RP2350 platforms, i.e. 
-`PICO_PLATFORM=rp2350-arm-s` or `PICO_PLATFORM=rp235-riscv`
+`PICO_PLATFORM=rp2350-arm-s` or `PICO_PLATFORM=rp2350-riscv`
 
 `hardware_regs` contains low level hardware register #defines autogenerated from the RP2350 chip definition itself.
 
diff --git a/src/rp2_common/hardware_dma/include/hardware/dma.h b/src/rp2_common/hardware_dma/include/hardware/dma.h
index 2ae64d5fa..599f8dd2e 100644
--- a/src/rp2_common/hardware_dma/include/hardware/dma.h
+++ b/src/rp2_common/hardware_dma/include/hardware/dma.h
@@ -556,6 +556,7 @@ static inline uint32_t dma_encode_transfer_count(uint transfer_count) {
  */
 static inline uint32_t dma_encode_transfer_count_with_self_trigger(uint transfer_count) {
 #if PICO_RP2040
+    (void)transfer_count;
     panic_unsupported();
 #else
     return dma_encode_transfer_count(transfer_count) | (DMA_CH0_TRANS_COUNT_MODE_VALUE_TRIGGER_SELF << DMA_CH0_TRANS_COUNT_MODE_LSB);
@@ -578,8 +579,8 @@ static inline uint32_t dma_encode_endless_transfer_count(void) {
 #if PICO_RP2040
     panic_unsupported();
 #else
-    static_assert(DMA_CH0_TRANS_COUNT_MODE_VALUE_ENDLESS == 0xf);
-    static_assert(DMA_CH0_TRANS_COUNT_MODE_LSB == 28);
+    static_assert(DMA_CH0_TRANS_COUNT_MODE_VALUE_ENDLESS == 0xf, "");
+    static_assert(DMA_CH0_TRANS_COUNT_MODE_LSB == 28, "");
     return 0xffffffffu;
 #endif
 }
diff --git a/src/rp2_common/hardware_gpio/gpio.c b/src/rp2_common/hardware_gpio/gpio.c
index 292041a19..a5560bbb8 100644
--- a/src/rp2_common/hardware_gpio/gpio.c
+++ b/src/rp2_common/hardware_gpio/gpio.c
@@ -196,9 +196,11 @@ void gpio_set_irq_enabled(uint gpio, uint32_t events, bool enabled) {
 }
 
 void gpio_set_irq_enabled_with_callback(uint gpio, uint32_t events, bool enabled, gpio_irq_callback_t callback) {
-    // first set callback, then enable the interrupt
-    gpio_set_irq_callback(callback);
+    // when enabling, first set callback, then enable the interrupt
+    // when disabling, first disable the interrupt, then clear callback
+    if (enabled) gpio_set_irq_callback(callback);
     gpio_set_irq_enabled(gpio, events, enabled);
+    if (!enabled) gpio_set_irq_callback(callback);
     if (enabled) irq_set_enabled(IO_IRQ_BANK0, true);
 }
 
diff --git a/src/rp2_common/hardware_hazard3/include/hardware/hazard3/instructions.h b/src/rp2_common/hardware_hazard3/include/hardware/hazard3/instructions.h
index 7abeb5ba6..f14b8c01c 100644
--- a/src/rp2_common/hardware_hazard3/include/hardware/hazard3/instructions.h
+++ b/src/rp2_common/hardware_hazard3/include/hardware/hazard3/instructions.h
@@ -128,7 +128,7 @@ extern "C" {
     __h3_bextmi_rd; \
 })
 #else
-#define __hazard3_bextm(nbits, rs1, rs2) (((rs1) >> ((shamt) & 0x1f)) & (0xffu >> (7 - (((nbits) - 1) & 0x7))))
+#define __hazard3_bextmi(nbits, rs1, rs2) (((rs1) >> ((shamt) & 0x1f)) & (0xffu >> (7 - (((nbits) - 1) & 0x7))))
 #endif
 
 #ifdef __hazard3_extension_xh3power
diff --git a/src/rp2_common/hardware_irq/irq.c b/src/rp2_common/hardware_irq/irq.c
index fc3d6f12c..fdcbb00fb 100644
--- a/src/rp2_common/hardware_irq/irq.c
+++ b/src/rp2_common/hardware_irq/irq.c
@@ -128,6 +128,15 @@ void irq_set_pending(uint num) {
 #endif
 }
 
+#if !PICO_NO_RAM_VECTOR_TABLE
+static void set_raw_irq_handler_and_unlock(uint num, irq_handler_t handler, uint32_t save) {
+    // update vtable (vtable_handler may be same or updated depending on cases, but we do it anyway for compactness)
+    get_vtable()[VTABLE_FIRST_IRQ + num] = handler;
+    __dmb();
+    spin_unlock(spin_lock_instance(PICO_SPINLOCK_ID_IRQ), save);
+}
+#endif
+
 #if !PICO_DISABLE_SHARED_IRQ_HANDLERS && !PICO_NO_RAM_VECTOR_TABLE
 // limited by 8 bit relative links (and reality)
 static_assert(PICO_MAX_SHARED_IRQ_HANDLERS >= 1 && PICO_MAX_SHARED_IRQ_HANDLERS < 0x7f, "");
@@ -202,13 +211,6 @@ bool irq_has_shared_handler(uint irq_num) {
     return is_shared_irq_raw_handler(handler);
 }
 
-static void set_raw_irq_handler_and_unlock(uint num, irq_handler_t handler, uint32_t save) {
-    // update vtable (vtable_handler may be same or updated depending on cases, but we do it anyway for compactness)
-    get_vtable()[VTABLE_FIRST_IRQ + num] = handler;
-    __dmb();
-    spin_unlock(spin_lock_instance(PICO_SPINLOCK_ID_IRQ), save);
-}
-
 #else // PICO_DISABLE_SHARED_IRQ_HANDLERS && PICO_NO_RAM_VECTOR_TABLE
 #define is_shared_irq_raw_handler(h) false
 bool irq_has_shared_handler(uint irq_num) {
diff --git a/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h b/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h
index e990a7284..85804f954 100644
--- a/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h
+++ b/src/rp2_common/hardware_pio/include/hardware/pio_instructions.h
@@ -148,7 +148,7 @@ static inline uint pio_encode_sideset(uint sideset_bit_count, uint value) {
  * \return the side set bits to be ORed with an instruction encoding
  */
 static inline uint pio_encode_sideset_opt(uint sideset_bit_count, uint value) {
-    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count >= 0 && sideset_bit_count <= 4);
+    valid_params_if(PIO_INSTRUCTIONS, sideset_bit_count <= 4);
     valid_params_if(PIO_INSTRUCTIONS, value <= ((1u << sideset_bit_count) - 1));
     return 0x1000u | value << (12u - sideset_bit_count);
 }
diff --git a/src/rp2_common/hardware_sync/include/hardware/sync.h b/src/rp2_common/hardware_sync/include/hardware/sync.h
index 69b3e69a0..14a86c888 100644
--- a/src/rp2_common/hardware_sync/include/hardware/sync.h
+++ b/src/rp2_common/hardware_sync/include/hardware/sync.h
@@ -94,6 +94,9 @@ __force_inline static void __sev(void) {
     pico_default_asm_volatile ("sev");
 #endif
 }
+#else
+// Forward declare so we don't have to #include <arm_acle.h>.
+void __sev(void);
 #endif
 
 /*! \brief Insert a WFE instruction in to the code path.
@@ -110,6 +113,9 @@ __force_inline static void __wfe(void) {
     pico_default_asm_volatile ("wfe");
 #endif
 }
+#else
+// Forward declare so we don't have to #include <arm_acle.h>.
+void __wfe(void);
 #endif
 
 /*! \brief Insert a WFI instruction in to the code path.
@@ -121,6 +127,9 @@ __force_inline static void __wfe(void) {
 __force_inline static void __wfi(void) {
     pico_default_asm_volatile("wfi");
 }
+#else
+// Forward declare so we don't have to #include <arm_acle.h>.
+void __wfi(void);
 #endif
 
 /*! \brief Insert a DMB instruction in to the code path.
diff --git a/src/rp2_common/pico_mbedtls/include/sha256_alt.h b/src/rp2_common/pico_mbedtls/include/sha256_alt.h
index b6658b2a7..78d9a9183 100644
--- a/src/rp2_common/pico_mbedtls/include/sha256_alt.h
+++ b/src/rp2_common/pico_mbedtls/include/sha256_alt.h
@@ -11,6 +11,6 @@
 #include "pico/sha256.h"
 
 typedef struct pico_sha256_state mbedtls_sha256_context;
-#endif // PICO_RP2350
+#endif // LIB_PICO_SHA256
 
 #endif
diff --git a/src/rp2_common/pico_multicore/multicore.c b/src/rp2_common/pico_multicore/multicore.c
index 219f24a16..e11595087 100644
--- a/src/rp2_common/pico_multicore/multicore.c
+++ b/src/rp2_common/pico_multicore/multicore.c
@@ -370,7 +370,7 @@ static bool multicore_doorbell_claim_under_lock(uint doorbell_num, uint core_mas
                                               (is_bit_claimed(doorbell_claimed[1], doorbell_num + 1u) << 1));
     if (claimed_cores_for_doorbell & core_mask) {
         if (required) {
-            panic( "Multicoore doorbell %d already claimed on core mask 0x%x; requested core mask 0x%x\n",
+            panic( "Multicore doorbell %d already claimed on core mask 0x%x; requested core mask 0x%x\n",
                    claimed_cores_for_doorbell, core_mask);
         }
         return false;
diff --git a/src/rp2_common/pico_status_led/CMakeLists.txt b/src/rp2_common/pico_status_led/CMakeLists.txt
index c14e607bf..cdc30bdf0 100644
--- a/src/rp2_common/pico_status_led/CMakeLists.txt
+++ b/src/rp2_common/pico_status_led/CMakeLists.txt
@@ -18,5 +18,3 @@ if (PICO_CYW43_SUPPORTED)
     )
 endif()
 pico_generate_pio_header(pico_status_led ${CMAKE_CURRENT_LIST_DIR}/ws2812.pio)
-
-get_target_property(OUT pico_status_led LINK_LIBRARIES)
diff --git a/src/rp2_common/pico_status_led/include/pico/status_led.h b/src/rp2_common/pico_status_led/include/pico/status_led.h
index be7c0bd49..4870bc9b6 100644
--- a/src/rp2_common/pico_status_led/include/pico/status_led.h
+++ b/src/rp2_common/pico_status_led/include/pico/status_led.h
@@ -109,7 +109,7 @@ bool status_led_init(void);
  *
  * \param context An \ref async_context used to communicate with the status LED (e.g. on Pico W or Pico 2 W)
  * \return Returns true if the LED was initialized successfully, otherwise false on failure
- * \sa status_led_init_with_context
+ * \sa status_led_init
  */
 bool status_led_init_with_context(struct async_context *context);
 
diff --git a/src/rp2_common/pico_status_led/status_led.c b/src/rp2_common/pico_status_led/status_led.c
index fc95a9689..309b21e73 100644
--- a/src/rp2_common/pico_status_led/status_led.c
+++ b/src/rp2_common/pico_status_led/status_led.c
@@ -80,7 +80,8 @@ bool colored_status_led_set_state(bool led_on) {
     if (colored_status_led_supported()) {
 #if COLORED_STATUS_LED_USING_WS2812_PIO
         success = true;
-        if (led_on && !colored_status_led_on) {
+        if (led_on) {
+            // Turn the LED "on" even if it was already on, as the color might have changed
             success = set_ws2812(colored_status_led_on_color);
         } else if (!led_on && colored_status_led_on) {
             success = set_ws2812(0);