diff --git a/src/cmake/rp2_common.cmake b/src/cmake/rp2_common.cmake
index 273839f70..f97775d8a 100644
--- a/src/cmake/rp2_common.cmake
+++ b/src/cmake/rp2_common.cmake
@@ -16,6 +16,7 @@ pico_add_subdirectory(common/pico_usb_reset_interface_headers)
 
 # PICO_CMAKE_CONFIG: PICO_BARE_METAL, Flag to exclude anything except base headers from the build, type=bool, default=0, group=build
 if (NOT PICO_BARE_METAL)
+    pico_add_subdirectory(common/pico_async_context)
     pico_add_subdirectory(common/pico_bit_ops_headers)
     pico_add_subdirectory(common/pico_binary_info)
     pico_add_subdirectory(common/pico_divider_headers)
@@ -124,7 +125,6 @@ if (NOT PICO_BARE_METAL)
     pico_add_subdirectory(rp2_common/pico_i2c_slave)
 
     # networking libraries - note dependency order is important
-    pico_add_subdirectory(rp2_common/pico_async_context)
     pico_add_subdirectory(rp2_common/pico_btstack)
     pico_add_subdirectory(rp2_common/pico_cyw43_driver)
     pico_add_subdirectory(rp2_common/pico_mbedtls)
diff --git a/src/rp2_common/pico_async_context/BUILD.bazel b/src/common/pico_async_context/BUILD.bazel
similarity index 62%
rename from src/rp2_common/pico_async_context/BUILD.bazel
rename to src/common/pico_async_context/BUILD.bazel
index a2de0acd2..e886858ae 100644
--- a/src/rp2_common/pico_async_context/BUILD.bazel
+++ b/src/common/pico_async_context/BUILD.bazel
@@ -20,11 +20,16 @@ cc_library(
         "include/pico/async_context_base.h",
     ],
     includes = ["include"],
-    target_compatible_with = compatible_with_rp2(),
     deps = [
         "//src/common/pico_time",
-        "//src/rp2_common:pico_platform",
-    ],
+    ] + select({
+        "//bazel/constraint:host": [
+            "//src/host/pico_platform",
+        ],
+        "//conditions:default": [
+            "//src/rp2_common:pico_platform",
+        ],
+    }),
 )
 
 cc_library(
@@ -32,7 +37,7 @@ cc_library(
     srcs = ["async_context_freertos.c"],
     hdrs = ["include/pico/async_context_freertos.h"],
     includes = ["include"],
-    target_compatible_with = compatible_with_rp2() + incompatible_with_config(
+    target_compatible_with = incompatible_with_config(
         "//bazel/constraint:pico_freertos_unset",
     ),
     deps = [
@@ -40,9 +45,16 @@ cc_library(
         "//bazel/config:PICO_FREERTOS_LIB",
         "//src/common/pico_sync",
         "//src/common/pico_time",
-        "//src/rp2_common:pico_platform",
-        "//src/rp2_common/hardware_irq",
-    ],
+    ] + select({
+        "//bazel/constraint:host": [
+            "//src/host/pico_platform",
+            "//src/host/hardware_irq",
+        ],
+        "//conditions:default": [
+            "//src/rp2_common:pico_platform",
+            "//src/rp2_common/hardware_irq",
+        ],
+    }),
 )
 
 cc_library(
@@ -50,13 +62,18 @@ cc_library(
     srcs = ["async_context_poll.c"],
     hdrs = ["include/pico/async_context_poll.h"],
     includes = ["include"],
-    target_compatible_with = compatible_with_rp2(),
     deps = [
         ":pico_async_context_base",
         "//src/common/pico_sync",
         "//src/common/pico_time",
-        "//src/rp2_common:pico_platform",
-    ],
+    ] + select({
+        "//bazel/constraint:host": [
+            "//src/host/pico_platform",
+        ],
+        "//conditions:default": [
+            "//src/rp2_common:pico_platform",
+        ],
+    }),
 )
 
 cc_library(
@@ -64,13 +81,20 @@ cc_library(
     srcs = ["async_context_threadsafe_background.c"],
     hdrs = ["include/pico/async_context_threadsafe_background.h"],
     includes = ["include"],
-    target_compatible_with = compatible_with_rp2(),
     deps = [
         ":pico_async_context_base",
         "//src/common/pico_sync",
         "//src/common/pico_time",
-        "//src/rp2_common:pico_platform",
-        "//src/rp2_common/hardware_irq",
-        "//src/rp2_common/pico_multicore",
-    ],
+    ] + select({
+        "//bazel/constraint:host": [
+            "//src/host/pico_platform",
+            "//src/host/hardware_irq",
+            "//src/host/pico_multicore",
+        ],
+        "//conditions:default": [
+            "//src/rp2_common:pico_platform",
+            "//src/rp2_common/hardware_irq",
+            "//src/rp2_common/pico_multicore",
+        ],
+    }),
 )
diff --git a/src/rp2_common/pico_async_context/CMakeLists.txt b/src/common/pico_async_context/CMakeLists.txt
similarity index 87%
rename from src/rp2_common/pico_async_context/CMakeLists.txt
rename to src/common/pico_async_context/CMakeLists.txt
index cb136aa2e..a2eb85a5a 100644
--- a/src/rp2_common/pico_async_context/CMakeLists.txt
+++ b/src/common/pico_async_context/CMakeLists.txt
@@ -15,10 +15,10 @@ pico_add_library(pico_async_context_threadsafe_background)
 target_sources(pico_async_context_threadsafe_background INTERFACE
         ${CMAKE_CURRENT_LIST_DIR}/async_context_threadsafe_background.c
         )
-pico_mirrored_target_link_libraries(pico_async_context_threadsafe_background INTERFACE pico_async_context_base)
+pico_mirrored_target_link_libraries(pico_async_context_threadsafe_background INTERFACE pico_async_context_base hardware_claim hardware_irq pico_multicore)
 
 pico_add_library(pico_async_context_freertos)
 target_sources(pico_async_context_freertos INTERFACE
         ${CMAKE_CURRENT_LIST_DIR}/async_context_freertos.c
         )
-pico_mirrored_target_link_libraries(pico_async_context_freertos INTERFACE pico_async_context_base)
+pico_mirrored_target_link_libraries(pico_async_context_freertos INTERFACE pico_async_context_base hardware_claim hardware_irq)
diff --git a/src/rp2_common/pico_async_context/async_context_base.c b/src/common/pico_async_context/async_context_base.c
similarity index 100%
rename from src/rp2_common/pico_async_context/async_context_base.c
rename to src/common/pico_async_context/async_context_base.c
diff --git a/src/rp2_common/pico_async_context/async_context_freertos.c b/src/common/pico_async_context/async_context_freertos.c
similarity index 100%
rename from src/rp2_common/pico_async_context/async_context_freertos.c
rename to src/common/pico_async_context/async_context_freertos.c
diff --git a/src/rp2_common/pico_async_context/async_context_poll.c b/src/common/pico_async_context/async_context_poll.c
similarity index 100%
rename from src/rp2_common/pico_async_context/async_context_poll.c
rename to src/common/pico_async_context/async_context_poll.c
diff --git a/src/rp2_common/pico_async_context/async_context_threadsafe_background.c b/src/common/pico_async_context/async_context_threadsafe_background.c
similarity index 100%
rename from src/rp2_common/pico_async_context/async_context_threadsafe_background.c
rename to src/common/pico_async_context/async_context_threadsafe_background.c
diff --git a/src/rp2_common/pico_async_context/include/pico/async_context.h b/src/common/pico_async_context/include/pico/async_context.h
similarity index 100%
rename from src/rp2_common/pico_async_context/include/pico/async_context.h
rename to src/common/pico_async_context/include/pico/async_context.h
diff --git a/src/rp2_common/pico_async_context/include/pico/async_context_base.h b/src/common/pico_async_context/include/pico/async_context_base.h
similarity index 100%
rename from src/rp2_common/pico_async_context/include/pico/async_context_base.h
rename to src/common/pico_async_context/include/pico/async_context_base.h
diff --git a/src/rp2_common/pico_async_context/include/pico/async_context_freertos.h b/src/common/pico_async_context/include/pico/async_context_freertos.h
similarity index 97%
rename from src/rp2_common/pico_async_context/include/pico/async_context_freertos.h
rename to src/common/pico_async_context/include/pico/async_context_freertos.h
index 0120410f7..26e19bc29 100644
--- a/src/rp2_common/pico_async_context/include/pico/async_context_freertos.h
+++ b/src/common/pico_async_context/include/pico/async_context_freertos.h
@@ -44,6 +44,13 @@ typedef struct async_context_freertos async_context_freertos_t;
 #endif
 #endif
 
+// On PICO_PLATFORM=host don't have ISR.
+#if !PICO_ON_DEVICE
+#ifndef portCHECK_IF_IN_ISR
+#define portCHECK_IF_IN_ISR() (0)
+#endif
+#endif
+
 /** 
  * \brief Configuration object for async_context_freertos instances.
  */
diff --git a/src/rp2_common/pico_async_context/include/pico/async_context_poll.h b/src/common/pico_async_context/include/pico/async_context_poll.h
similarity index 100%
rename from src/rp2_common/pico_async_context/include/pico/async_context_poll.h
rename to src/common/pico_async_context/include/pico/async_context_poll.h
diff --git a/src/rp2_common/pico_async_context/include/pico/async_context_threadsafe_background.h b/src/common/pico_async_context/include/pico/async_context_threadsafe_background.h
similarity index 100%
rename from src/rp2_common/pico_async_context/include/pico/async_context_threadsafe_background.h
rename to src/common/pico_async_context/include/pico/async_context_threadsafe_background.h
diff --git a/src/host.cmake b/src/host.cmake
index 10cafc7f9..ecea8a6cf 100644
--- a/src/host.cmake
+++ b/src/host.cmake
@@ -9,7 +9,8 @@ include (${CMAKE_DIR}/no_hardware.cmake)
  pico_add_subdirectory(${COMMON_DIR}/boot_picobin_headers)
  pico_add_subdirectory(${COMMON_DIR}/boot_picoboot_headers)
  pico_add_subdirectory(${COMMON_DIR}/boot_uf2_headers)
- pico_add_subdirectory(${COMMON_DIR}/hardware_claim) 
+ pico_add_subdirectory(${COMMON_DIR}/hardware_claim)
+ pico_add_subdirectory(${COMMON_DIR}/pico_async_context)
  pico_add_subdirectory(${COMMON_DIR}/pico_base_headers)
  pico_add_subdirectory(${COMMON_DIR}/pico_usb_reset_interface_headers)
  pico_add_subdirectory(${COMMON_DIR}/pico_bit_ops_headers)
diff --git a/src/host/hardware_irq/BUILD.bazel b/src/host/hardware_irq/BUILD.bazel
index af055a468..6a53f8ded 100644
--- a/src/host/hardware_irq/BUILD.bazel
+++ b/src/host/hardware_irq/BUILD.bazel
@@ -8,7 +8,7 @@ cc_library(
     tags = ["manual"],  # TODO: No hardware/regs/intctrl.h for host yet.
     target_compatible_with = ["//bazel/constraint:host"],
     deps = [
-        "//src/host/hardware_claim",
+        "//src/common/hardware_claim",
         "//src/host/pico_platform",
     ],
 )
diff --git a/src/host/pico_multicore/BUILD.bazel b/src/host/pico_multicore/BUILD.bazel
index b837fb5de..1e76e2ae6 100644
--- a/src/host/pico_multicore/BUILD.bazel
+++ b/src/host/pico_multicore/BUILD.bazel
@@ -3,6 +3,7 @@ package(default_visibility = ["//visibility:public"])
 cc_library(
     name = "pico_multicore",
     hdrs = ["include/pico/multicore.h"],
+    defines = ["LIB_PICO_MULTICORE=1"],
     includes = ["include"],
     target_compatible_with = ["//bazel/constraint:host"],
     deps = ["//src/host/pico_platform"],
diff --git a/src/host/pico_platform/include/hardware/platform_defs.h b/src/host/pico_platform/include/hardware/platform_defs.h
index c1a6f5f44..f91765e1a 100644
--- a/src/host/pico_platform/include/hardware/platform_defs.h
+++ b/src/host/pico_platform/include/hardware/platform_defs.h
@@ -18,6 +18,7 @@
 #define NUM_USER_IRQS 6u
 #define FIRST_USER_IRQ (NUM_IRQS - NUM_USER_IRQS)
 #define VTABLE_FIRST_IRQ 16
+#define PICO_NUM_VTABLE_IRQS NUM_IRQS
 
 #define NUM_SPIN_LOCKS 32u
 
diff --git a/src/host/pico_platform/include/pico/platform.h b/src/host/pico_platform/include/pico/platform.h
index 0338354e5..1bfd5896d 100644
--- a/src/host/pico_platform/include/pico/platform.h
+++ b/src/host/pico_platform/include/pico/platform.h
@@ -128,6 +128,12 @@ void __noreturn panic_unsupported();
 
 void __noreturn panic(const char *fmt, ...);
 
+#ifdef NDEBUG
+#define panic_compact(...) panic(__VA_ARGS__)
+#else
+#define panic_compact(...) panic("")
+#endif
+
 // arggggghhhh there is a weak function called sem_init used by SDL
 #define sem_init sem_init_alternative
 
diff --git a/src/rp2_common/pico_btstack/BUILD.bazel b/src/rp2_common/pico_btstack/BUILD.bazel
index 5d88ad690..c7322ad92 100644
--- a/src/rp2_common/pico_btstack/BUILD.bazel
+++ b/src/rp2_common/pico_btstack/BUILD.bazel
@@ -87,7 +87,7 @@ cc_library(
     target_compatible_with = compatible_with_pico_w(),
     deps = [
         "//src/rp2_common/hardware_sync",
-        "//src/rp2_common/pico_async_context",
+        "//src/common/pico_async_context",
         "@btstack//:pico_btstack_base",
     ],
 )
diff --git a/src/rp2_common/pico_cyw43_arch/BUILD.bazel b/src/rp2_common/pico_cyw43_arch/BUILD.bazel
index 286184e73..ee8b25c72 100644
--- a/src/rp2_common/pico_cyw43_arch/BUILD.bazel
+++ b/src/rp2_common/pico_cyw43_arch/BUILD.bazel
@@ -75,7 +75,7 @@ _CONFIGURATIONS = [
         ),
         deps = [
             "//src/rp2_common:pico_platform",
-            "//src/rp2_common/pico_async_context:pico_async_context_{}".format(kind),
+            "//src/common/pico_async_context:pico_async_context_{}".format(kind),
             "//src/rp2_common/pico_cyw43_driver",
             "//src/rp2_common/pico_unique_id",
         ] + (
diff --git a/src/rp2_common/pico_cyw43_driver/BUILD.bazel b/src/rp2_common/pico_cyw43_driver/BUILD.bazel
index 3810b27c2..9bdbe28c1 100644
--- a/src/rp2_common/pico_cyw43_driver/BUILD.bazel
+++ b/src/rp2_common/pico_cyw43_driver/BUILD.bazel
@@ -34,7 +34,7 @@ cc_library(
         "//src/rp2_common/hardware_irq",
         "//src/rp2_common/hardware_pio",
         "//src/rp2_common/hardware_sync",
-        "//src/rp2_common/pico_async_context",
+        "//src/common/pico_async_context",
         "//src/rp2_common/pico_unique_id",
         "@cyw43-driver//:cyw43_driver",
     ] + select({
diff --git a/src/rp2_common/pico_lwip/BUILD.bazel b/src/rp2_common/pico_lwip/BUILD.bazel
index cc5de44c8..0fc03e215 100644
--- a/src/rp2_common/pico_lwip/BUILD.bazel
+++ b/src/rp2_common/pico_lwip/BUILD.bazel
@@ -22,7 +22,7 @@ cc_library(
         ":pico_lwip",
         "//src/common/pico_time",
         "//src/rp2_common:pico_platform",
-        "//src/rp2_common/pico_async_context",
+        "//src/common/pico_async_context",
         "//src/rp2_common/pico_rand",
     ],
     alwayslink = True,
@@ -38,7 +38,7 @@ cc_library(
         ":pico_lwip",
         "//src/common/pico_time",
         "//src/rp2_common:pico_platform",
-        "//src/rp2_common/pico_async_context",
+        "//src/common/pico_async_context",
         "//src/rp2_common/pico_rand",
     ],
     alwayslink = True,
diff --git a/tools/build_all_headers.py b/tools/build_all_headers.py
index a3e4f04b3..b54a2c127 100755
--- a/tools/build_all_headers.py
+++ b/tools/build_all_headers.py
@@ -20,9 +20,9 @@
 IGNORE_DIRS = set(['host', 'boards'])
 IGNORE_DIRS.add('common/boot_picoboot')
 IGNORE_DIRS.add('common/boot_uf2')
+IGNORE_DIRS.add('common/pico_async_context')
 IGNORE_DIRS.add('common/pico_usb_reset_interface')
 IGNORE_DIRS.add('rp2_common/cmsis')
-IGNORE_DIRS.add('rp2_common/pico_async_context')
 IGNORE_DIRS.add('rp2_common/pico_btstack')
 #IGNORE_DIRS.add('rp2_common/pico_cyw43_arch')
 IGNORE_DIRS.add('rp2_common/pico_cyw43_driver')