diff --git a/platform/linuxbsd/detect.py b/platform/linuxbsd/detect.py
index 2fd573da757..c8202b147d2 100644
--- a/platform/linuxbsd/detect.py
+++ b/platform/linuxbsd/detect.py
@@ -279,16 +279,18 @@ def configure(env: "SConsEnvironment"):
         env.ParseConfig("pkg-config libwebp --cflags --libs")
 
     if not env["builtin_mbedtls"]:
-        # mbedTLS does not provide a pkgconfig config yet. See https://github.com/ARMmbed/mbedtls/issues/228
-        env.Append(LIBS=["mbedtls", "mbedcrypto", "mbedx509"])
+        # mbedTLS only provides a pkgconfig file since 3.6.0, but we still support 2.28.x,
+        # so fallback to manually specifying LIBS if it fails.
+        if os.system("pkg-config --exists mbedtls") == 0:  # 0 means found
+            env.ParseConfig("pkg-config mbedtls mbedcrypto mbedx509 --cflags --libs")
+        else:
+            env.Append(LIBS=["mbedtls", "mbedcrypto", "mbedx509"])
 
     if not env["builtin_wslay"]:
         env.ParseConfig("pkg-config libwslay --cflags --libs")
 
     if not env["builtin_miniupnpc"]:
-        # No pkgconfig file so far, hardcode default paths.
-        env.Prepend(CPPPATH=["/usr/include/miniupnpc"])
-        env.Append(LIBS=["miniupnpc"])
+        env.ParseConfig("pkg-config miniupnpc --cflags --libs")
 
     # On Linux wchar_t should be 32-bits
     # 16-bit library shouldn't be required due to compiler optimizations