diff --git a/pkgs/by-name/ap/applgrid/TFileStringLinkDef.h b/pkgs/by-name/ap/applgrid/TFileStringLinkDef.h
new file mode 100644
index 000000000000..ce59a4a65321
--- /dev/null
+++ b/pkgs/by-name/ap/applgrid/TFileStringLinkDef.h
@@ -0,0 +1,6 @@
+#ifdef __CLING__
+#pragma link off all globals;
+#pragma link off all classes;
+#pragma link off all functions;
+#pragma link C++ class TFileString+;
+#endif
diff --git a/pkgs/by-name/ap/applgrid/TFileVectorLinkDef.h b/pkgs/by-name/ap/applgrid/TFileVectorLinkDef.h
new file mode 100644
index 000000000000..07ba83655d5e
--- /dev/null
+++ b/pkgs/by-name/ap/applgrid/TFileVectorLinkDef.h
@@ -0,0 +1,6 @@
+#ifdef __CLING__
+#pragma link off all globals;
+#pragma link off all classes;
+#pragma link off all functions;
+#pragma link C++ class TFileVector+;
+#endif
diff --git a/pkgs/by-name/ap/applgrid/no-m64.patch b/pkgs/by-name/ap/applgrid/no-m64.patch
new file mode 100644
index 000000000000..5848af7d1e3e
--- /dev/null
+++ b/pkgs/by-name/ap/applgrid/no-m64.patch
@@ -0,0 +1,10 @@
+--- a/configure
++++ b/configure
+@@ -16130,7 +16130,6 @@
+ $as_echo "$as_me: WARNING: ****************************************************************" >&2;}
+ fi
+ 
+-( echo $CXXFLAGS | grep -q "m64" ) || CXXFLAGS+=" -m64 "
+ 
+ 
+ 
diff --git a/pkgs/by-name/ap/applgrid/package.nix b/pkgs/by-name/ap/applgrid/package.nix
index c578ade96705..bda97414b7a2 100644
--- a/pkgs/by-name/ap/applgrid/package.nix
+++ b/pkgs/by-name/ap/applgrid/package.nix
@@ -18,7 +18,26 @@ stdenv.mkDerivation (finalAttrs: {
     hash = "sha256-h+ZNGj33FIwg4fOCyfGJrUKM2vDDQl76JcLhtboAOtc=";
   };
 
+  patches = [
+    # Upstream's configure unconditionally injects `-m64` into CXXFLAGS, which is
+    # invalid on aarch64 (and redundant on x86_64). The line was added in r1946
+    # for applgrid 1.6.17 with the commit message "add default m64 compilation".
+    # There is no public bug tracker upstream, and the line is still present in
+    # trunk. We patch only the generated `configure` (not `configure.ac`) so
+    # that make doesn't try to re-run autotools during the build.
+    ./no-m64.patch
+
+    # ROOT 6.40 made rootcling fail when no selection rules are provided
+    # (https://root.cern/doc/v640/release-notes.html#core-libraries). The patch
+    # appends $*LinkDef.h to the dictionary pattern rule so rootcint picks up
+    # the LinkDef.h files we drop into src/ in postPatch.
+    ./rootcling-linkdef.patch
+  ];
+
   postPatch = ''
+    cp ${./TFileStringLinkDef.h} src/TFileStringLinkDef.h
+    cp ${./TFileVectorLinkDef.h} src/TFileVectorLinkDef.h
+
     sed -i appl_grid/serialise_base.h -e '1i#include <cstdint>'
   '';
 
diff --git a/pkgs/by-name/ap/applgrid/rootcling-linkdef.patch b/pkgs/by-name/ap/applgrid/rootcling-linkdef.patch
new file mode 100644
index 000000000000..e969dc7f25c7
--- /dev/null
+++ b/pkgs/by-name/ap/applgrid/rootcling-linkdef.patch
@@ -0,0 +1,11 @@
+--- a/src/Makefile.in
++++ b/src/Makefile.in
+@@ -1027,7 +1027,7 @@
+ 	$(CC) $(AM_CFLAGS) -c $<
+ 
+ @USE_ROOT_TRUE@%Dict.cxx : %.h %.cxx
+-@USE_ROOT_TRUE@	$(CINT) -f $@ -c $< -I.. 
++@USE_ROOT_TRUE@	$(CINT) -f $@ -c $< -I.. $*LinkDef.h
+ 
+ #../appl_grid/$*LinkDef.h
+