diff '--color=auto' -Naur a/lib/freebl/Makefile b/lib/freebl/Makefile
--- a/lib/freebl/Makefile	2026-09-09 19:46:15.505386235 +0300
+++ b/lib/freebl/Makefile	2026-09-09 19:47:22.985375793 +0300
@@ -654,7 +654,16 @@
                libcrux_mldsa_core.c libcrux_mldsa_portable.c \
                libcrux_mldsa44_portable.c libcrux_mldsa65_portable.c \
                libcrux_mldsa87_portable.c
+# Bug 2067434 - restrict these to the child build that compiles the real
+# library. The parent (loader-only) and lowhash stub builds reset CSRCS to their
+# single source file, and appending here bypasses that. The stub build shares
+# its OBJDIR with the real single-shlib build, so under make -jN both would
+# compile these to the same object files at once, producing truncated objects.
+ifdef FREEBL_CHILD_BUILD
+ifndef USE_STUB_BUILD
 CSRCS += $(LIBCRUX_SRCS)
+endif
+endif
 
 # Bug 1918767 / Bug 1918711 - by setting KRML_MUSTINLINE=inline here, we
 # avoid it being defined to `inline __forceinline` (for msvc) or `inline