diff --git a/support/testing/infra/basetest.py b/support/testing/infra/basetest.py
index 13f9b2d398..5fa902a77f 100644
--- a/support/testing/infra/basetest.py
+++ b/support/testing/infra/basetest.py
@@ -1,6 +1,9 @@
 import unittest
 import os
+import dataclasses
 import datetime
+import json
+from typing import ClassVar
 
 from infra.builder import Builder
 from infra.emulator import Emulator
@@ -22,6 +25,33 @@ MINIMAL_CONFIG = \
     """
 
 
+@dataclasses.dataclass
+class BRTestSettings:
+    """support/testing/run-tests stores runtime settings in this
+    object, and serializes it into the environment variable named in
+    CONF_ENV. On instantiation, BRConfigTest loads this
+    configuration. That way configuration can be transferred into
+    multiprocessing worker processes without requiring the "fork"
+    start method.
+
+    """
+    CONF_ENV: ClassVar[str] = 'BR_TEST_CONFIG_JSON'
+
+    downloaddir: str
+    outputdir: str
+    logtofile: bool = True
+    keepbuilds: bool = False
+    jlevel: int = 0
+    timeout_multiplier: int = 1
+
+    def to_env(self) -> None:
+        os.environ[self.CONF_ENV] = json.dumps(dataclasses.asdict(self))
+
+    @classmethod
+    def from_env(cls) -> 'BRTestSettings':
+        return cls(**json.loads(os.environ[cls.CONF_ENV]))
+
+
 class BRConfigTest(unittest.TestCase):
     """Test up to the configure stage."""
     config: str
@@ -35,6 +65,8 @@ class BRConfigTest(unittest.TestCase):
 
     def __init__(self, names):
         super(BRConfigTest, self).__init__(names)
+        if BRTestSettings.CONF_ENV in os.environ:
+            self.conf_from_env()
         self.testname = self.__class__.__name__
         self.builddir = self.outputdir and os.path.join(self.outputdir, self.testname)
         self.config += '\nBR2_DL_DIR="{}"\n'.format(self.downloaddir)
@@ -44,6 +76,11 @@ class BRConfigTest(unittest.TestCase):
         print("{} {:40s} {}".format(datetime.datetime.now().strftime("%H:%M:%S"),
                                     self.testname, msg))
 
+    def conf_from_env(self) -> None:
+        conf = BRTestSettings.from_env()
+        for f in dataclasses.fields(conf):
+            setattr(self, f.name, getattr(conf, f.name))
+
     def setUp(self):
         self.show_msg("Starting")
         self.b = Builder(self.config, self.builddir, self.logtofile, self.jlevel)
diff --git a/support/testing/run-tests b/support/testing/run-tests
index 2c7ce87c96..f0c1cc782a 100755
--- a/support/testing/run-tests
+++ b/support/testing/run-tests
@@ -6,7 +6,7 @@ import sys
 
 import nose2
 
-from infra.basetest import BRConfigTest
+from infra.basetest import BRTestSettings
 
 import infra
 
@@ -44,9 +44,6 @@ def main():
     script_path = os.path.realpath(__file__)
     test_dir = os.path.dirname(script_path)
 
-    if args.stdout:
-        BRConfigTest.logtofile = False
-
     if args.list:
         print("List of tests")
         nose2_args = [
@@ -69,7 +66,7 @@ def main():
             parser.print_help()
             return 1
 
-    BRConfigTest.downloaddir = os.path.abspath(args.download)
+    args.download = os.path.abspath(args.download)
 
     if args.prepare_only:
         emulator_builtin_binaries = ["kernel-vexpress-5.10.202",
@@ -78,7 +75,7 @@ def main():
                                      "versatile-pb-5.10.202.dtb"]
         print("Downloading emulator builtin binaries")
         for binary in emulator_builtin_binaries:
-            infra.download(BRConfigTest.downloaddir, binary)
+            infra.download(args.download, binary)
         return 0
 
     if args.output is None:
@@ -90,15 +87,13 @@ def main():
     if not os.path.exists(args.output):
         os.mkdir(args.output)
 
-    BRConfigTest.outputdir = os.path.abspath(args.output)
-
     if args.all is False and not args.testname:
         print("No test selected")
         print("")
         parser.print_help()
         return 1
 
-    BRConfigTest.keepbuilds = args.keep
+    jlevel = 0
 
     if args.testcases != 1:
         if args.testcases < 1:
@@ -109,7 +104,7 @@ def main():
         # same default BR2_JLEVEL as package/Makefile.in
         br2_jlevel = 1 + multiprocessing.cpu_count()
         each_testcase = int((br2_jlevel + args.testcases) / args.testcases)
-        BRConfigTest.jlevel = each_testcase
+        jlevel = each_testcase
 
     if args.jlevel:
         if args.jlevel < 0:
@@ -118,14 +113,22 @@ def main():
             parser.print_help()
             return 1
         # the user can override the auto calculated value
-        BRConfigTest.jlevel = args.jlevel
+        jlevel = args.jlevel
 
     if args.timeout_multiplier < 1:
         print("Invalid multiplier for timeout values")
         print("")
         parser.print_help()
         return 1
-    BRConfigTest.timeout_multiplier = args.timeout_multiplier
+
+    BRTestSettings(
+        logtofile=not args.stdout,
+        downloaddir=args.download,
+        outputdir=os.path.abspath(args.output),
+        keepbuilds=args.keep,
+        jlevel=jlevel,
+        timeout_multiplier=args.timeout_multiplier
+    ).to_env()
 
     nose2_args = ["-v",
                   "-N", str(args.testcases),
@@ -142,15 +145,4 @@ def main():
 
 
 if __name__ == "__main__":
-    # python 3.14 changed default start method from fork to
-    # fork-server, which is not compatible with the nose2 setup
-    if multiprocessing.get_start_method(allow_none=True) != "fork":
-        multiprocessing.set_start_method("fork", force=True)
-        # set_start_method throws a RuntimeError if called more than
-        # once.
-        # Debian python3-nose2 0.15.1-2 includes a patch adding
-        # another set_start_method() call, so monkey patch it out to
-        # get rid of this
-        multiprocessing.set_start_method = lambda *args: None
-
     sys.exit(main())