diff --git a/misc/onnxruntime/Makefile b/misc/onnxruntime/Makefile
index 3446f8609c1e..6f32222fa9c0 100644
--- a/misc/onnxruntime/Makefile
+++ b/misc/onnxruntime/Makefile
@@ -1,69 +1,70 @@
 PORTNAME=	onnxruntime
 DISTVERSIONPREFIX=	v
 DISTVERSION=	1.27.0
+PORTREVISION=	1
 CATEGORIES=	misc # machine-learning
 DIST_SUBDIR=	${PORTNAME}
 
 MAINTAINER=	yuri@FreeBSD.org
 COMMENT=	Cross-platform, high performance ML inferencing & training accelerator
 WWW=		https://onnxruntime.ai/ \
 		https://github.com/microsoft/onnxruntime
 
 LICENSE=	MIT
 LICENSE_FILE=	${WRKSRC}/LICENSE
 
 BROKEN_i386=	compilation fails: error: requested alignment is less than minimum alignment of 8 for type 'google::protobuf::internal::ThreadSafeArena::CacheAlignedLifecycleIdGenerator'
 
 BUILD_DEPENDS=	gpatch:devel/patch
 
 USES=		cmake:testing compiler:c++11-lang python:build
 USE_LDCONFIG=	yes
 
 USE_GITHUB=	yes
 GH_ACCOUNT=	microsoft
 GH_TUPLE=	emscripten-core:emsdk:0742117:emsdk/cmake/external/emsdk \
 		google:libprotobuf-mutator:7a2ed51a6b682a83e345ff49fc4cfd7ca47550db:libprotobuf_mutator/cmake/external/libprotobuf-mutator \
 		onnx:onnx:b8baa8446686496da4cc8fda09f2b6fe65c2a02c:onnx/cmake/external/onnx
 
 CMAKE_SOURCE_PATH=	${WRKSRC}/cmake
 CMAKE_ON=	onnxruntime_BUILD_SHARED_LIB
 CMAKE_OFF=	FETCHCONTENT_FULLY_DISCONNECTED \
 		onnxruntime_BUILD_UNIT_TESTS
 CMAKE_ARGS=	-Donnx_SOURCE_DIR=${WRKSRC}/cmake/external/onnx
 CMAKE_TESTING_ON=	onnxruntime_BUILD_UNIT_TESTS
 
 CXXFLAGS+=	-Wno-array-bounds # workaround for https://github.com/microsoft/onnxruntime/issues/23410
 CXXFLAGS+=	-Wno-deprecated-declarations #fixes error: 'vec_lvsl' is deprecated: use assignment for unaligned little endian loads/stores
 #CXXFLAGS+=	-Wno-deprecated-altivec-src-compat #fixes error: current handling of vector bool and vector pixel types in this context are deprecated; the default behaviour will soon change to that implied by the '-altivec-compat=xl' option
 CXXFLAGS+=	-I${WRKSRC}/include/onnxruntime/core/common/logging # otherwise logging.h isn't found
 CXXFLAGS+=	-frtti # fixes error: onnxruntime/test/contrib_ops/gather_block_quantized_op_test.cc:85:77: error: use of typeid requires -frtti
-CXXFLAGS_powerpc64=	-mvsx
+CXXFLAGS_powerpc64=	-Wno-error=deprecated-altivec-src-compat
 
 BINARY_ALIAS=	patch=gpatch
 
 DEPS_FILE=	${WRKSRC}/cmake/deps.txt
 
 CONFLICTS_BUILD=	abseil benchmark nsync googletest dlpack flatbuffers gsl mimalloc \
 			nlohmann-json onnx protobuf psimd pthreadpool pybind11 re2
 
 dev-update-deps-in-makefiles: extract # this should be run when the port is updated
 	@${FILESDIR}/convert-deps.sh ${DEPS_FILE}
 
 pre-configure:
 	@${REINPLACE_CMD} -E 's|;(https://.*)/([^/]+\.zip);|;file://${DISTDIR}/${DIST_SUBDIR}/\2;|' ${DEPS_FILE}
 	# correct one mismatching hash
 	#@${REINPLACE_CMD} -E 's|1094e3bb7a8af763dcb136ccd676e6e75e614eec|5d2b21b10478556c5e209dd7229e298a5c9f0b02|' ${DEPS_FILE}
 
 # NOTE there should be an EXTRACT_ONLY statement
 # NOTE shared libs can't be enabled because the build would fail, see discussion in this issue: https://github.com/microsoft/onnxruntime/issues/22331
 
 # tests as of 1.21.1 (cd work/.build && ./onnxruntime_test_all):
 # [==========] 4743 tests from 310 test suites ran. (321548 ms total)
 # [  PASSED  ] 4732 tests.
 # [  FAILED  ] 1 test, listed below:
 # [  FAILED  ] OptimizerInitializerTest.LoadExternalData
 # see https://github.com/microsoft/onnxruntime/issues/23816
 
 .include <Makefile.MASTER_SITES>
 .include <Makefile.DISTFILES>
 .include <bsd.port.mk>
diff --git a/misc/onnxruntime/files/patch-cmake_onnxruntime__mlas.cmake b/misc/onnxruntime/files/patch-cmake_onnxruntime__mlas.cmake
new file mode 100644
index 000000000000..48533c5b1f52
--- /dev/null
+++ b/misc/onnxruntime/files/patch-cmake_onnxruntime__mlas.cmake
@@ -0,0 +1,18 @@
+--- cmake/onnxruntime_mlas.cmake.orig	2026-09-02 19:55:21 UTC
++++ cmake/onnxruntime_mlas.cmake
+@@ -617,6 +617,15 @@ else()
+         endif()
+     endif()
+     if(POWER AND MLAS_SOURCE_IS_NOT_SET)
++        check_cxx_source_compiles("
++          #ifndef __VSX__
++          #error VSX is not supported
++          #endif
++          int main() { return 0; }"
++          MLAS_HAS_VSX
++        )
++    endif()
++    if(POWER AND MLAS_HAS_VSX AND MLAS_SOURCE_IS_NOT_SET)
+         set(mlas_platform_srcs
+           ${MLAS_SRC_DIR}/power/SgemmKernelPower.cpp
+           ${MLAS_SRC_DIR}/dgemm.cpp