diff --git a/.github/workflows/end2end_tests.yaml b/.github/workflows/end2end_tests.yaml
index bb04309..bdc04ea 100644
--- a/.github/workflows/end2end_tests.yaml
+++ b/.github/workflows/end2end_tests.yaml
@@ -45,6 +45,10 @@ jobs:
         CONSTRAINTS_FILE="$GITHUB_WORKSPACE/constraints.txt"
         echo "setuptools<82" > "$CONSTRAINTS_FILE"
         export PIP_CONSTRAINT="$CONSTRAINTS_FILE"
+        # pip >= 26.2 no longer applies PIP_CONSTRAINT to isolated build
+        # environments (needed for the mmcv sdist build, see
+        # https://github.com/open-mmlab/mmcv/issues/3325)
+        export PIP_BUILD_CONSTRAINT="$CONSTRAINTS_FILE"
         pip install -e .[dev]
 
     - name: Run full public tests
@@ -93,6 +97,10 @@ jobs:
         CONSTRAINTS_FILE="$GITHUB_WORKSPACE/constraints.txt"
         echo "setuptools<82" > "$CONSTRAINTS_FILE"
         export PIP_CONSTRAINT="$CONSTRAINTS_FILE"
+        # pip >= 26.2 no longer applies PIP_CONSTRAINT to isolated build
+        # environments (needed for the mmcv sdist build, see
+        # https://github.com/open-mmlab/mmcv/issues/3325)
+        export PIP_BUILD_CONSTRAINT="$CONSTRAINTS_FILE"
         pip install -e .[dev]
 
     - name: Run representative public tests
diff --git a/.github/workflows/unittests.yaml b/.github/workflows/unittests.yaml
index a307644..9bc3956 100644
--- a/.github/workflows/unittests.yaml
+++ b/.github/workflows/unittests.yaml
@@ -60,8 +60,12 @@ jobs:
       working-directory: ${{ inputs.tools_ref != '' && 'tools' || '' }}
       run: |
         CONSTRAINTS_FILE="$GITHUB_WORKSPACE/constraints.txt"
-        echo "setuptools<81" > "$CONSTRAINTS_FILE"
+        echo "setuptools<82" > "$CONSTRAINTS_FILE"
         export PIP_CONSTRAINT="$CONSTRAINTS_FILE"
+        # pip >= 26.2 no longer applies PIP_CONSTRAINT to isolated build
+        # environments (needed for the mmcv sdist build, see
+        # https://github.com/open-mmlab/mmcv/issues/3325)
+        export PIP_BUILD_CONSTRAINT="$CONSTRAINTS_FILE"
         pip install -e .[dev]
         pip install coverage-badge>=1.1.0 pytest-cov>=4.1.0
 
@@ -72,6 +76,9 @@ jobs:
       env:
         ML_REF: ${{ inputs.ml_ref }}
       run: |
+        CONSTRAINTS_FILE="$GITHUB_WORKSPACE/constraints.txt"
+        export PIP_CONSTRAINT="$CONSTRAINTS_FILE"
+        export PIP_BUILD_CONSTRAINT="$CONSTRAINTS_FILE"
         pip uninstall luxonis-ml -y
         pip install \
           "luxonis-ml[data,nn-archive,utils] @ git+https://github.com/luxonis/luxonis-ml.git@${ML_REF}" \
diff --git a/README.md b/README.md
index dd6c0da..da5228b 100644
--- a/README.md
+++ b/README.md
@@ -36,7 +36,9 @@ cd tools
 
 ```bash
 # Install the package
-PIP_CONSTRAINT=constraints.txt pip install .
+# (PIP_BUILD_CONSTRAINT is required with pip >= 26.2, which no longer
+# applies PIP_CONSTRAINT to isolated build environments)
+PIP_CONSTRAINT=constraints.txt PIP_BUILD_CONSTRAINT=constraints.txt pip install .
 # Running the package
 tools yolov6nr4.pt --imgsz "416"
 ```