diff --git a/mpy-cross/mpy_cross/__init__.py b/mpy-cross/mpy_cross/__init__.py
index d4c0930bb9198..8eadbc8352c74 100644
--- a/mpy-cross/mpy_cross/__init__.py
+++ b/mpy-cross/mpy_cross/__init__.py
@@ -27,47 +27,76 @@
 
 from __future__ import print_function
 import os
+import re
 import stat
 import subprocess
 
-NATIVE_ARCH_X86 = "x86"
-NATIVE_ARCH_X64 = "x64"
-NATIVE_ARCH_ARMV6 = "armv6"
-NATIVE_ARCH_ARMV6M = "armv6m"
-NATIVE_ARCH_ARMV7M = "armv7m"
-NATIVE_ARCH_ARMV7EM = "armv7em"
-NATIVE_ARCH_ARMV7EMSP = "armv7emsp"
-NATIVE_ARCH_ARMV7EMDP = "armv7emdp"
-NATIVE_ARCH_XTENSA = "xtensa"
-NATIVE_ARCH_XTENSAWIN = "xtensawin"
-
-NATIVE_ARCHS = [
-    NATIVE_ARCH_X86,
-    NATIVE_ARCH_X64,
-    NATIVE_ARCH_ARMV6,
-    NATIVE_ARCH_ARMV6M,
-    NATIVE_ARCH_ARMV7M,
-    NATIVE_ARCH_ARMV7EM,
-    NATIVE_ARCH_ARMV7EMSP,
-    NATIVE_ARCH_ARMV7EMDP,
-    NATIVE_ARCH_XTENSA,
-    NATIVE_ARCH_XTENSAWIN,
-]
-
-__all__ = ["compile", "run", "CrossCompileError"]
+NATIVE_ARCHS = {
+    "NATIVE_ARCH_NONE": "",
+    "NATIVE_ARCH_X86": "x86",
+    "NATIVE_ARCH_X64": "x64",
+    "NATIVE_ARCH_ARMV6": "armv6",
+    "NATIVE_ARCH_ARMV6M": "armv6m",
+    "NATIVE_ARCH_ARMV7M": "armv7m",
+    "NATIVE_ARCH_ARMV7EM": "armv7em",
+    "NATIVE_ARCH_ARMV7EMSP": "armv7emsp",
+    "NATIVE_ARCH_ARMV7EMDP": "armv7emdp",
+    "NATIVE_ARCH_XTENSA": "xtensa",
+    "NATIVE_ARCH_XTENSAWIN": "xtensawin",
+}
+
+globals().update(NATIVE_ARCHS)
+
+__all__ = ["version", "compile", "run", "CrossCompileError"] + list(NATIVE_ARCHS.keys())
 
 
 class CrossCompileError(Exception):
     pass
 
 
-def find_mpy_cross_binary(mpy_cross):
+_VERSION_RE = re.compile("mpy-cross emitting mpy v([0-9]+)(?:.([0-9]+))?")
+
+
+def _find_mpy_cross_binary(mpy_cross):
     if mpy_cross:
         return mpy_cross
-    return os.path.abspath(os.path.join(os.path.dirname(__file__), "../mpy-cross"))
+    return os.path.abspath(os.path.join(os.path.dirname(__file__), "../build/mpy-cross"))
+
+
+def mpy_version(mpy_cross=None):
+    """
+    Get the version and sub-version of the .mpy file format generated by this version of mpy-cross.
+
+    Returns: A tuple of `(mpy_version, mpy_sub_version)`
+    Optional keyword arguments:
+     - mpy_cross: Specific mpy-cross binary to use
+    """
+    version_info = run(["--version"], mpy_cross=mpy_cross)
+    match = re.search(_VERSION_RE, version_info)
+    mpy_version, mpy_sub_version = int(match.group(1)), int(match.group(2) or "0")
+    return (
+        mpy_version,
+        mpy_sub_version,
+    )
 
 
 def compile(src, dest=None, src_path=None, opt=None, march=None, mpy_cross=None, extra_args=None):
+    """
+    Compile the specified .py file with mpy-cross.
+
+    Returns: Standard output from mpy-cross as a string.
+
+    Required arguments:
+     - src:        The path to the .py file
+
+    Optional keyword arguments:
+     - dest:       The output .mpy file. Defaults to `src` (with .mpy extension)
+     - src_path:   The path to embed in the .mpy file (defaults to `src`)
+     - opt:        Optimisation level (0-3, default 0)
+     - march:      One of the `NATIVE_ARCH_*` constants (defaults to NATIVE_ARCH_NONE)
+     - mpy_cross:  Specific mpy-cross binary to use
+     - extra_args: Additional arguments to pass to mpy-cross (e.g. `["-X", "emit=native"]`)
+    """
     if not src:
         raise ValueError("src is required")
     if not os.path.exists(src):
@@ -82,7 +111,7 @@ def compile(src, dest=None, src_path=None, opt=None, march=None, mpy_cross=None,
         args += ["-o", dest]
 
     if march:
-        args += ["-march", march]
+        args += ["-march=" + march]
 
     if opt is not None:
         args += ["-O{}".format(opt)]
@@ -96,7 +125,16 @@ def compile(src, dest=None, src_path=None, opt=None, march=None, mpy_cross=None,
 
 
 def run(args, mpy_cross=None):
-    mpy_cross = find_mpy_cross_binary(mpy_cross)
+    """
+    Run mpy-cross with the specified command line arguments.
+    Prefer to use `compile()` instead.
+
+    Returns: Standard output from mpy-cross as a string.
+
+    Optional keyword arguments:
+     - mpy_cross: Specific mpy-cross binary to use
+    """
+    mpy_cross = _find_mpy_cross_binary(mpy_cross)
 
     if not os.path.exists(mpy_cross):
         raise CrossCompileError("mpy-cross binary not found at {}.".format(mpy_cross))
@@ -108,6 +146,6 @@ def run(args, mpy_cross=None):
         pass
 
     try:
-        subprocess.check_output([mpy_cross] + args, stderr=subprocess.STDOUT)
+        return subprocess.check_output([mpy_cross] + args, stderr=subprocess.STDOUT).decode()
     except subprocess.CalledProcessError as er:
-        raise CrossCompileError(er.output)
+        raise CrossCompileError(er.output.decode())
diff --git a/mpy-cross/mpy_cross/__main__.py b/mpy-cross/mpy_cross/__main__.py
index 9d957bca025d6..2b6b81c333362 100644
--- a/mpy-cross/mpy_cross/__main__.py
+++ b/mpy-cross/mpy_cross/__main__.py
@@ -32,7 +32,7 @@
 from . import run, CrossCompileError
 
 try:
-    run(sys.argv[1:])
+    print(run(sys.argv[1:]))
 except CrossCompileError as er:
     print(er.args[0], file=sys.stderr)
     raise SystemExit(1)