diff --git a/CMakeLists.txt b/CMakeLists.txt
index 9abca561f3..03f97eb7e5 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -50,7 +50,9 @@ CMAKE_DEPENDENT_OPTION(ENABLE_SDL2 "Enable the SDL2 frontend" ON "NOT ANDROID" O
 
 set(EXT_DEFAULT ON)
 
-if (PLATFORM_FREEBSD)
+# See https://github.com/llvm/llvm-project/issues/123946
+# OpenBSD va_list doesn't play nice with precompiled headers
+if (PLATFORM_FREEBSD OR PLATFORM_OPENBSD)
     set(EXT_DEFAULT OFF)
 endif()
 
diff --git a/README.md b/README.md
index 70f2c81296..e1f0b50b37 100644
--- a/README.md
+++ b/README.md
@@ -63,6 +63,7 @@ If you would like to contribute, we are open to new developers and pull requests
 * **Solaris**: [Solaris Building Guide](./docs/build/Solaris.md)
 * **FreeBSD**: [FreeBSD Building Guide](./docs/build/FreeBSD.md)
 * **macOS**: [macOS Building Guide](./docs/build/macOS.md)
+* **OpenBSD**: [OpenBSD Building Guide](./docs/build/OpenBSD.md)
 
 ## Download
 
diff --git a/docs/Development.md b/docs/Development.md
index e60384e8ab..e4816cd1ec 100644
--- a/docs/Development.md
+++ b/docs/Development.md
@@ -6,6 +6,7 @@
 * **Solaris**: [Solaris Building Guide](./build/Solaris.md)
 * **FreeBSD**: [FreeBSD Building Guide](./build/FreeBSD.md)
 * **macOS**: [macOS Building Guide](./build/macOS.md)
+* **OpenBSD**: [OpenBSD Building Guide](./build/OpenBSD.md)
 
 # CPM
 
diff --git a/docs/build/OpenBSD.md b/docs/build/OpenBSD.md
new file mode 100644
index 0000000000..29f2fc9ab9
--- /dev/null
+++ b/docs/build/OpenBSD.md
@@ -0,0 +1,15 @@
+# Building for OpenBSD
+
+```sh
+pkg_add -u
+pkg_add cmake nasm git boost unzip--iconv autoconf-2.72p0 bash ffmpeg glslang g++-11.2.0p18 gmake
+git --recursive https://git.eden-emu.dev/eden-emu/eden
+```
+
+Select g++-11.2. The compiler can then be invoked via `ec++`.
+
+```sh
+cmake -DDYNARMIC_USE_PRECOMPILED_HEADERS=OFF -DCMAKE_BUILD_TYPE=Debug -DENABLE_QT=OFF -DENABLE_OPENSSL=OFF -DENABLE_WEB_SERVICE=OFF -B /usr/obj/eden
+```
+
+- Modify `externals/ffmpeg/CMakeFiles/ffmpeg-build/build.make` to use `-j$(nproc)` instead of just `-j`.
diff --git a/src/core/debugger/debugger.cpp b/src/core/debugger/debugger.cpp
index 7fe22fdce2..460e0d19b4 100644
--- a/src/core/debugger/debugger.cpp
+++ b/src/core/debugger/debugger.cpp
@@ -7,7 +7,7 @@
 #include <boost/asio.hpp>
 #include <boost/version.hpp>
 
-#if BOOST_VERSION > 108300 && (!defined(_WINDOWS) && !defined(ANDROID)) || defined(YUZU_BOOST_v1)
+#if BOOST_VERSION > 108400 && (!defined(_WINDOWS) && !defined(ANDROID)) || defined(YUZU_BOOST_v1)
 #define USE_BOOST_v1
 #endif
 
diff --git a/src/dynarmic/externals/CMakeLists.txt b/src/dynarmic/externals/CMakeLists.txt
index ba70797a84..23cfd42236 100644
--- a/src/dynarmic/externals/CMakeLists.txt
+++ b/src/dynarmic/externals/CMakeLists.txt
@@ -62,10 +62,10 @@ AddJsonPackage(
 
 # unordered_dense
 
-# AddJsonPackage(
-#     NAME unordered-dense
-#     BUNDLED_PACKAGE ${DYNARMIC_USE_BUNDLED_EXTERNALS}
-# )
+AddJsonPackage(
+    NAME unordered-dense
+    BUNDLED_PACKAGE ${DYNARMIC_USE_BUNDLED_EXTERNALS}
+)
 
 # xbyak
 # uncomment if in an independent repo