diff --git a/tools/legacy/build_plugin_zstd_vs2026.py b/tools/legacy/build_plugin_zstd_vs2026.py
index 1707e11..20794d5 100644
--- a/tools/legacy/build_plugin_zstd_vs2026.py
+++ b/tools/legacy/build_plugin_zstd_vs2026.py
@@ -5,7 +5,7 @@ Supports multiple build configurations with flexible parameters.
 Uses PlatformToolset v145 (Visual Studio 2026 Build Tools).
 
 The 7-Zip ZS source is pulled from the git submodule at versions/7-zip-zstd/.
-The NSIS plugin wrapper (nsis7z.cpp, vcxproj, …) lives in versions/zstd/.
+The NSIS plugin wrapper (nsis7z.cpp, vcxproj, …) lives in versions/zstd-bundle/.
 
 NOTE: VS2026 Build Tools use v145 toolset (version 18.x)
 """
@@ -201,7 +201,7 @@ def find_msbuild(vs_version: str = 'auto') -> 'Optional[Tuple[Path, str, str]]':
 def get_project_paths(toolset: str = 'v145') -> Tuple[Path, Path, Path]:
     """Get project directory, project file, and plugins directory"""
     script_dir = Path(__file__).parent.absolute()
-    project_dir = script_dir.parent.parent / 'versions' / 'zstd'
+    project_dir = script_dir.parent.parent / 'versions' / 'zstd-bundle'
     vcxproj = 'Nsis7z_vs2026.vcxproj'
     project_file = project_dir / 'CPP' / '7zip' / 'Bundles' / 'Nsis7z' / vcxproj
     plugins_dir = script_dir.parent.parent / 'plugins'
diff --git a/tools/linux/build_plugin_linux.py b/tools/linux/build_plugin_linux.py
index fffa665..6426b38 100644
--- a/tools/linux/build_plugin_linux.py
+++ b/tools/linux/build_plugin_linux.py
@@ -29,7 +29,7 @@ SUPPORTED = {"25.01", "26.00", "26.01", "zstd"}
 # project-owned sources (NSIS UI, wrapper cpp files, vcxproj).
 #
 # For zstd the 7-zip C++ sources live in the 7-zip-zstd submodule while our
-# NSIS wrapper sits in versions/zstd/.  make is run with -C pointing to the
+# NSIS wrapper sits in versions/zstd-bundle/.  make is run with -C pointing to the
 # wrapper dir and VENDOR_7ZIP overridden to the submodule tree so that
 # include/source rules resolve correctly without touching the submodule.
 VERSION_LAYOUT = {
@@ -48,10 +48,19 @@ VERSION_LAYOUT = {
     # zstd: make runs in our wrapper dir; vendor_7zip points to submodule tree.
     "zstd": {
         "vendor_7zip": ROOT / "versions" / "7-zip-zstd" / "CPP" / "7zip",
-        "bundle_dir":  ROOT / "versions" / "zstd" / "CPP" / "7zip" / "Bundles" / "Nsis7z",
+        "bundle_dir":  ROOT / "versions" / "zstd-bundle" / "CPP" / "7zip" / "Bundles" / "Nsis7z",
     },
 }
 
+# Per-version extra flags for GCC/MinGW cross-compilation that apply to both
+# C and C++ compilations.  Passed via LOCAL_FLAGS_EXTRA → merged into CFLAGS
+# and CXXFLAGS alike.
+VERSION_EXTRA_FLAGS: dict[str, str] = {
+    # fast-lzma2 (part of the 7-zip-zstd vendor) triggers -Wsign-compare and
+    # -Wcast-function-type on C code that was never compiled with GCC -Werror.
+    "zstd": "-Wno-sign-compare -Wno-cast-function-type",
+}
+
 # Per-version C++-only extra flags for GCC/MinGW cross-compilation.
 # These compensate for vendor code written exclusively for MSVC.
 # Passed via LOCAL_CXXFLAGS_EXTRA → appended to CXXFLAGS only (not CFLAGS).
@@ -67,6 +76,10 @@ VERSION_EXTRA_CXXFLAGS: dict[str, str] = {
     #     in the specific makefile rule for NsisExtractCallbackConsole.o.
     #   - Several unused parameters and sign-compare on UInt64 vs. literal -1.
     "25.01": "-Wno-sign-compare -Wno-unused-parameter",
+    # 7-zip-zstd NSIS UI code has the same unused-parameter issues as 25.01.
+    # sign-compare is in C code (fast-lzma2) and already in VERSION_EXTRA_FLAGS;
+    # unused-parameter warnings are C++-only (NSIS wrapper and nsis7z.cpp).
+    "zstd": "-Wno-unused-parameter",
 }
 
 CONFIGS = {
@@ -144,7 +157,7 @@ def _build_one(
     bundle_dir  = layout["bundle_dir"]
 
     # Symlinks are not committed to git; recreate them on Linux if missing.
-    if zip_version in VERSION_LAYOUT and zip_version != "zstd":
+    if zip_version in VERSION_LAYOUT:
         _ensure_bundle_symlinks(zip_version, bundle_dir, vendor_7zip)
 
     cfg = CONFIGS[cfg_name]
@@ -166,7 +179,8 @@ def _build_one(
     # Version-specific workarounds for vendor code that was MSVC-only.
     # Flags that are C++-only (e.g. -fpermissive) must go into LOCAL_CXXFLAGS_EXTRA
     # which the makefile appends only to CXXFLAGS, not to CFLAGS.
-    extra_cxx = VERSION_EXTRA_CXXFLAGS.get(zip_version, "")
+    extra_flags = VERSION_EXTRA_FLAGS.get(zip_version, "")
+    extra_cxx   = VERSION_EXTRA_CXXFLAGS.get(zip_version, "")
 
     # CXX_INCLUDE_FLAGS:
     #   1. overlay/include – case-sensitivity shims (Windows.h → windows.h, …)
@@ -179,6 +193,11 @@ def _build_one(
     # our bundle dir, not in the vendor tree.  Override NSIS_DIR accordingly.
     bundle_nsis = bundle_dir.parent.parent / "UI" / "NSIS"
 
+    # The 7-zip-zstd vendor calls LocalFileTimeToFileTime2() which is defined
+    # in MyWindows.cpp.  That TU is normally excluded from SYS_OBJS when
+    # IS_MINGW=1, so we must inject it back via EXTRA_SYS_OBJS.
+    extra_sys_objs = f"{out_dir}/MyWindows.o" if zip_version == "zstd" else ""
+
     base_cmd = [
         "make",
         "-C", str(bundle_dir),
@@ -194,8 +213,9 @@ def _build_one(
         f"CC={triplet}-gcc",
         f"CXX={triplet}-g++",
         f"RC={triplet}-windres",
-        f"LOCAL_FLAGS_EXTRA={local_flags} -Wno-unknown-pragmas",
+        f"LOCAL_FLAGS_EXTRA={local_flags} -Wno-unknown-pragmas {extra_flags}".rstrip(),
         f"LOCAL_CXXFLAGS_EXTRA={extra_cxx}",
+        *([ f"EXTRA_SYS_OBJS={extra_sys_objs}" ] if extra_sys_objs else []),
         # Linux ld is case-sensitive; vendor makefile uses mixed-case lib names
         # (lUser32, lOle32, …) that don't exist on disk.  Override LIB2 with
         # fully-expanded lowercase equivalents.
diff --git a/tools/linux/overlay/makefile.gcc b/tools/linux/overlay/makefile.gcc
index f713ebe..e4cdf78 100644
--- a/tools/linux/overlay/makefile.gcc
+++ b/tools/linux/overlay/makefile.gcc
@@ -73,9 +73,15 @@ CURRENT_OBJS = \
   $O/pluginapi.o \
   $O/nsis7z.o \
 
+# Optional extra system objects – pass from the command line when the vendor
+# requires additional translation units that are normally excluded for mingw
+# (e.g. MyWindows.o for the 7-zip-zstd variant).
+EXTRA_SYS_OBJS ?=
+
 OBJS = \
   $(ARC_OBJS) \
   $(SYS_OBJS) \
+  $(EXTRA_SYS_OBJS) \
   $(NSIS_UI_OBJS) \
   $(CURRENT_OBJS) \
 
diff --git a/tools/linux/setup_bundle_symlinks.py b/tools/linux/setup_bundle_symlinks.py
index 86869ae..667f094 100644
--- a/tools/linux/setup_bundle_symlinks.py
+++ b/tools/linux/setup_bundle_symlinks.py
@@ -8,6 +8,7 @@ Example:
     python3 setup_bundle_symlinks.py 25.01
     python3 setup_bundle_symlinks.py 26.00
     python3 setup_bundle_symlinks.py 26.01
+    python3 setup_bundle_symlinks.py zstd
 """
 import os
 import sys
@@ -19,9 +20,14 @@ if len(sys.argv) != 2:
 
 version = sys.argv[1]
 
+# For versions where the vendor directory name differs from the bundle version key.
+VENDOR_DIR = {
+    "zstd": "7-zip-zstd",
+}
+
 ROOT = Path(__file__).resolve().parents[2]
 bundle_root = ROOT / f"versions/{version}-bundle"
-vendor_root = ROOT / f"versions/{version}"
+vendor_root = ROOT / "versions" / VENDOR_DIR.get(version, version)
 
 if not vendor_root.exists():
     print(f"Error: vendor directory not found: {vendor_root}", file=sys.stderr)
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/Nsis7z_vs2026.vcxproj b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/Nsis7z_vs2026.vcxproj
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/Nsis7z_vs2026.vcxproj
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/Nsis7z_vs2026.vcxproj
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/StdAfx.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/StdAfx.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/StdAfx.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/StdAfx.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/StdAfx2.cpp b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/StdAfx2.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/StdAfx2.cpp
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/StdAfx2.cpp
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/afxres.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/afxres.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/afxres.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/afxres.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/api.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/api.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/api.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/api.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/nsis7z.cpp b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/nsis7z.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/nsis7z.cpp
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/nsis7z.cpp
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/nsis_tchar.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/nsis_tchar.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/nsis_tchar.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/nsis_tchar.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/pluginapi.cpp b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/pluginapi.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/pluginapi.cpp
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/pluginapi.cpp
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/pluginapi.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/pluginapi.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/pluginapi.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/pluginapi.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/resource.h b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/resource.h
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/resource.h
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/resource.h
diff --git a/versions/zstd/CPP/7zip/Bundles/Nsis7z/resource.rc b/versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/resource.rc
similarity index 100%
rename from versions/zstd/CPP/7zip/Bundles/Nsis7z/resource.rc
rename to versions/zstd-bundle/CPP/7zip/Bundles/Nsis7z/resource.rc
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/ExtractCallbackConsole.cpp b/versions/zstd-bundle/CPP/7zip/UI/NSIS/ExtractCallbackConsole.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/ExtractCallbackConsole.cpp
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/ExtractCallbackConsole.cpp
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/ExtractCallbackConsole.h b/versions/zstd-bundle/CPP/7zip/UI/NSIS/ExtractCallbackConsole.h
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/ExtractCallbackConsole.h
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/ExtractCallbackConsole.h
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/Main.cpp b/versions/zstd-bundle/CPP/7zip/UI/NSIS/Main.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/Main.cpp
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/Main.cpp
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/MainAr.cpp b/versions/zstd-bundle/CPP/7zip/UI/NSIS/MainAr.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/MainAr.cpp
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/MainAr.cpp
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/NSISBreak.cpp b/versions/zstd-bundle/CPP/7zip/UI/NSIS/NSISBreak.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/NSISBreak.cpp
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/NSISBreak.cpp
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/NSISBreak.h b/versions/zstd-bundle/CPP/7zip/UI/NSIS/NSISBreak.h
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/NSISBreak.h
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/NSISBreak.h
diff --git a/versions/zstd-bundle/CPP/7zip/UI/NSIS/StdAfx.h b/versions/zstd-bundle/CPP/7zip/UI/NSIS/StdAfx.h
new file mode 100644
index 0000000..9f06ac9
--- /dev/null
+++ b/versions/zstd-bundle/CPP/7zip/UI/NSIS/StdAfx.h
@@ -0,0 +1,15 @@
+// StdAfx.h
+
+#ifndef __STDAFX_H
+#define __STDAFX_H
+
+#ifdef _WIN32
+  #if defined(__MINGW32__) || defined(__MINGW64__)
+    #include <windows.h>
+  #else
+    #include <Windows.h>
+  #endif
+#endif
+#include "../../Bundles/Nsis7z/pluginapi.h"
+
+#endif
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/UserInputUtils2.cpp b/versions/zstd-bundle/CPP/7zip/UI/NSIS/UserInputUtils2.cpp
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/UserInputUtils2.cpp
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/UserInputUtils2.cpp
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/UserInputUtils2.h b/versions/zstd-bundle/CPP/7zip/UI/NSIS/UserInputUtils2.h
similarity index 100%
rename from versions/zstd/CPP/7zip/UI/NSIS/UserInputUtils2.h
rename to versions/zstd-bundle/CPP/7zip/UI/NSIS/UserInputUtils2.h
diff --git a/versions/zstd/CPP/7zip/UI/NSIS/StdAfx.h b/versions/zstd/CPP/7zip/UI/NSIS/StdAfx.h
deleted file mode 100644
index c8c5279..0000000
--- a/versions/zstd/CPP/7zip/UI/NSIS/StdAfx.h
+++ /dev/null
@@ -1,9 +0,0 @@
-// StdAfx.h
-
-#ifndef __STDAFX_H
-#define __STDAFX_H
-
-#include <Windows.h>
-#include "7zip/Bundles/Nsis7z/pluginapi.h"
-
-#endif