diff --git a/bin/spc-alpine-docker b/bin/spc-alpine-docker
index 204273e3..df71ae25 100755
--- a/bin/spc-alpine-docker
+++ b/bin/spc-alpine-docker
@@ -3,7 +3,7 @@
 set -e
 
 # This file is using docker to run commands
-SPC_DOCKER_VERSION=v5
+SPC_DOCKER_VERSION=v6
 
 # Detect docker can run
 if ! which docker >/dev/null; then
@@ -122,6 +122,9 @@ ADD ./src /app/src
 COPY ./composer.* /app/
 ADD ./bin /app/bin
 RUN composer install --no-dev
+ADD ./config /app/config
+RUN PKG_ROOT_PATH=/app/pkgroot-private bin/spc doctor --auto-fix
+RUN PKG_ROOT_PATH=/app/pkgroot-private bin/spc install-pkg upx
 EOF
 fi
 
diff --git a/bin/spc-gnu-docker b/bin/spc-gnu-docker
index 0d708492..6b92fe82 100755
--- a/bin/spc-gnu-docker
+++ b/bin/spc-gnu-docker
@@ -3,7 +3,7 @@
 set -e
 
 # This file is using docker to run commands
-SPC_DOCKER_VERSION=v5
+SPC_DOCKER_VERSION=v6
 
 # Detect docker can run
 if ! which docker >/dev/null; then
@@ -112,7 +112,8 @@ ENV SPC_LIBC=glibc
 ENV PATH="/app/bin:/cmake/bin:/opt/rh/devtoolset-10/root/usr/bin:\$PATH"
 
 ADD ./config /app/config
-RUN CC=gcc bin/spc doctor --auto-fix --debug
+RUN CC=gcc PKG_ROOT_PATH=/app/pkgroot-private bin/spc doctor --auto-fix --debug
+RUN PKG_ROOT_PATH=/app/pkgroot-private bin/spc install-pkg upx
 RUN if [ -f /app/buildroot/bin/re2c ]; then \
         cp /app/buildroot/bin/re2c /usr/local/bin/re2c ;\
     fi
diff --git a/src/SPC/doctor/item/PkgConfigCheck.php b/src/SPC/doctor/item/PkgConfigCheck.php
index 0936a606..1d758b48 100644
--- a/src/SPC/doctor/item/PkgConfigCheck.php
+++ b/src/SPC/doctor/item/PkgConfigCheck.php
@@ -29,6 +29,18 @@ class PkgConfigCheck
         return CheckResult::ok($pkgconf);
     }
 
+    #[AsCheckItem('if pkg-config is working', level: 799)]
+    public function checkPkgConfigFunctional(): CheckResult
+    {
+        $pkgconf = PkgConfigUtil::findPkgConfig();
+        // check if pkg-config is functional
+        [$ret, $output] = shell()->execWithResult("{$pkgconf} --version", false);
+        if ($ret === 0) {
+            return CheckResult::ok(implode(' ', $output));
+        }
+        return CheckResult::fail('pkg-config is not functional', 'install-pkgconfig');
+    }
+
     #[AsFixItem('install-pkgconfig')]
     public function installPkgConfig(): bool
     {
diff --git a/src/SPC/util/GlobalEnvManager.php b/src/SPC/util/GlobalEnvManager.php
index 9f74d2df..073394a7 100644
--- a/src/SPC/util/GlobalEnvManager.php
+++ b/src/SPC/util/GlobalEnvManager.php
@@ -40,6 +40,10 @@ class GlobalEnvManager
         if (is_unix()) {
             self::addPathIfNotExists(BUILD_BIN_PATH);
             self::addPathIfNotExists(PKG_ROOT_PATH . '/bin');
+            // internally use `WORKING_DIR/pkgroot-private` to avoid volume mount issues in Docker
+            if (is_dir(WORKING_DIR . '/pkgroot-private/bin')) {
+                self::addPathIfNotExists(WORKING_DIR . '/pkgroot-private/bin');
+            }
             self::putenv('PKG_CONFIG_PATH=' . BUILD_LIB_PATH . '/pkgconfig');
         }
 
diff --git a/src/SPC/util/PkgConfigUtil.php b/src/SPC/util/PkgConfigUtil.php
index 25e0e1f2..14c2691f 100644
--- a/src/SPC/util/PkgConfigUtil.php
+++ b/src/SPC/util/PkgConfigUtil.php
@@ -23,6 +23,7 @@ class PkgConfigUtil
     {
         // Find pkg-config executable
         $find_list = [
+            WORKING_DIR . '/pkgroot-private/bin/pkg-config', // used in Docker build, which is installed inside the container to avoid volume mounting issues
             PKG_ROOT_PATH . '/bin/pkg-config',
             BUILD_BIN_PATH . '/pkg-config',
         ];