Index: tools/yaml2obj/yaml2elf.cpp
===================================================================
--- tools/yaml2obj/yaml2elf.cpp
+++ tools/yaml2obj/yaml2elf.cpp
@@ -358,11 +358,9 @@
 
   for (const auto &Rel : Section.Relocations) {
     unsigned SymIdx;
-    if (SymN2I.lookup(Rel.Symbol, SymIdx)) {
-      errs() << "error: Unknown symbol referenced: '" << Rel.Symbol
-             << "' at YAML relocation.\n";
-      return false;
-    }
+    // Some special relocation, R_ARM_v4BX for instance, does not have
+    // an external reference.
+    SymN2I.lookup(Rel.Symbol, SymIdx);
 
     if (IsRela) {
       Elf_Rela REntry;