diff --git a/.github/workflows/build.yml b/.github/workflows/build.yml
index 90ebde9062..6f260117ad 100644
--- a/.github/workflows/build.yml
+++ b/.github/workflows/build.yml
@@ -400,7 +400,7 @@ jobs:
       id: idf-cache
       with:
         path: ${{ github.workspace }}/.idf_tools
-        key: ${{ runner.os }}-idf-tools-${{ hashFiles('.git/modules/ports/espressif/esp-idf/HEAD') }}-20210923
+        key: ${{ runner.os }}-idf-tools-${{ hashFiles('.git/modules/ports/espressif/esp-idf/HEAD') }}-20220404
     - name: Clone IDF submodules
       run: |
         (cd $IDF_PATH && git submodule update --init)
diff --git a/ports/nrf/common-hal/pwmio/PWMOut.c b/ports/nrf/common-hal/pwmio/PWMOut.c
index 76c8c4e6d4..27c0b79b5a 100644
--- a/ports/nrf/common-hal/pwmio/PWMOut.c
+++ b/ports/nrf/common-hal/pwmio/PWMOut.c
@@ -108,6 +108,7 @@ STATIC void reset_single_pwmout(uint8_t i) {
 
     for (int ch = 0; ch < CHANNELS_PER_PWM; ch++) {
         pwm_seq[i][ch] = (1 << 15); // polarity = 0
+        pwm->PSEL.OUT[ch] = 0xFFFFFFFF; // disconnnect from I/O
     }
 }
 
diff --git a/ports/raspberrypi/common-hal/busio/UART.c b/ports/raspberrypi/common-hal/busio/UART.c
index 0e25c57297..9fd5ad3168 100644
--- a/ports/raspberrypi/common-hal/busio/UART.c
+++ b/ports/raspberrypi/common-hal/busio/UART.c
@@ -85,7 +85,7 @@ static void shared_callback(busio_uart_obj_t *self) {
     _copy_into_ringbuf(&self->ringbuf, self->uart);
     // We always clear the interrupt so it doesn't continue to fire because we
     // may not have read everything available.
-    uart_get_hw(self->uart)->icr = UART_UARTICR_RXIC_BITS;
+    uart_get_hw(self->uart)->icr = UART_UARTICR_RXIC_BITS | UART_UARTICR_RTIC_BITS;
 }
 
 static void uart0_callback(void) {
diff --git a/py/ringbuf.c b/py/ringbuf.c
index 72e164946a..fe47b50068 100644
--- a/py/ringbuf.c
+++ b/py/ringbuf.c
@@ -28,7 +28,6 @@
 #include "ringbuf.h"
 
 bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t capacity) {
-    r->heap = false;
     r->buf = buf;
     r->size = capacity;
     r->iget = r->iput = 0;
@@ -40,7 +39,6 @@ bool ringbuf_init(ringbuf_t *r, uint8_t *buf, size_t capacity) {
 // size of the buffer is one greater than that, due to how the buffer
 // handles empty and full statuses.
 bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived) {
-    r->heap = true;
     r->buf = gc_alloc(capacity + 1, false, long_lived);
     r->size = capacity + 1;
     r->iget = r->iput = 0;
@@ -48,9 +46,8 @@ bool ringbuf_alloc(ringbuf_t *r, size_t capacity, bool long_lived) {
 }
 
 void ringbuf_free(ringbuf_t *r) {
-    if (r->heap) {
-        gc_free(r->buf);
-    }
+    // Free buf by letting gc take care of it. If the VM has finished already,
+    // this will be safe.
     r->buf = (uint8_t *)NULL;
     r->size = 0;
     ringbuf_clear(r);
diff --git a/py/ringbuf.h b/py/ringbuf.h
index 8f7e7b1760..d868eff1e4 100644
--- a/py/ringbuf.h
+++ b/py/ringbuf.h
@@ -37,7 +37,6 @@ typedef struct _ringbuf_t {
     uint32_t size;
     uint32_t iget;
     uint32_t iput;
-    bool heap;
 } ringbuf_t;
 
 // Note that the capacity of the buffer is N-1!
diff --git a/py/vm.c b/py/vm.c
index 63eb7f46d9..8cb01d3552 100644
--- a/py/vm.c
+++ b/py/vm.c
@@ -739,8 +739,8 @@ unwind_jump:;
                     obj = mp_getiter(obj, iter_buf);
                     if (obj != MP_OBJ_FROM_PTR(iter_buf)) {
                         // Iterator didn't use the stack so indicate that with MP_OBJ_NULL.
-                        sp[-MP_OBJ_ITER_BUF_NSLOTS + 1] = MP_OBJ_NULL;
-                        sp[-MP_OBJ_ITER_BUF_NSLOTS + 2] = obj;
+                        *(sp - MP_OBJ_ITER_BUF_NSLOTS + 1) = MP_OBJ_NULL;
+                        *(sp - MP_OBJ_ITER_BUF_NSLOTS + 2) = obj;
                     }
                     DISPATCH();
                 }
@@ -751,8 +751,8 @@ unwind_jump:;
                     DECODE_ULABEL; // the jump offset if iteration finishes; for labels are always forward
                     code_state->sp = sp;
                     mp_obj_t obj;
-                    if (sp[-MP_OBJ_ITER_BUF_NSLOTS + 1] == MP_OBJ_NULL) {
-                        obj = sp[-MP_OBJ_ITER_BUF_NSLOTS + 2];
+                    if (*(sp - MP_OBJ_ITER_BUF_NSLOTS + 1) == MP_OBJ_NULL) {
+                        obj = *(sp - MP_OBJ_ITER_BUF_NSLOTS + 2);
                     } else {
                         obj = MP_OBJ_FROM_PTR(&sp[-MP_OBJ_ITER_BUF_NSLOTS + 1]);
                     }
diff --git a/requirements-dev.txt b/requirements-dev.txt
index 9c574567f7..67835dad3d 100644
--- a/requirements-dev.txt
+++ b/requirements-dev.txt
@@ -4,10 +4,12 @@ huffman
 # For nvm.toml
 cascadetoml
 jinja2
-typer
+# Undo this pin when click and typer are again compatible.
+typer==0.4.0
 
 sh
-click
+# Undo this pin when click and typer are again compatible.
+click==8.0.4
 cpp-coveralls
 requests
 requests-cache
diff --git a/shared-module/audiomp3/MP3Decoder.c b/shared-module/audiomp3/MP3Decoder.c
index 2d45313814..d0aecc18bd 100644
--- a/shared-module/audiomp3/MP3Decoder.c
+++ b/shared-module/audiomp3/MP3Decoder.c
@@ -364,7 +364,7 @@ audioio_get_buffer_result_t audiomp3_mp3file_get_buffer(audiomp3_mp3file_obj_t *
     }
 
     self->samples_decoded += *buffer_length / sizeof(int16_t);
-    return GET_BUFFER_MORE_DATA;
+    return mp3file_find_sync_word(self) ? GET_BUFFER_MORE_DATA : GET_BUFFER_DONE;
 }
 
 void audiomp3_mp3file_get_buffer_structure(audiomp3_mp3file_obj_t *self, bool single_channel_output,