Module loading on rakudo-j broken

gistfile1.txt

$ ./perl6-j -Ilib -e 'use Test'
===SORRY!===
This type cannot unbox to a native string

$ ./perl6-j -e 'use NoSuchModule'
===SORRY!===
This type cannot unbox to a native string

$ RAKUDO_MODULE_DEBUG=1 ./perl6-j -Ilib -e 'use Test'
     43108 RMD: Loading settings CORE
     43108 RMD: Setting up default paths: . blib
     43108 RMD: going to load Perl6::BOOTSTRAP
     43108 RMD: Settings CORE loaded
 295 43108 RMD: Attempting 'Test' as a pragma
  95 43108 RMD:   'Test' is not a valid pragma
  26 43108 RMD: Attempting to load 'Test'
  19 43108 RMD:   Late loading 'Test'
  23 43108 RMD: Parsing specs: lib
  32 43108 RMD: Parsing specs: 
  15 43108 RMD: Parsing specs: .
  17 43108 RMD: Parsing specs: blib
  23 43108 RMD: Parsing specs: /usr/home/christian/perl6/perl6-roast-data/rakudo.jvm/install/share/nqp/lib
===SORRY!===
This type cannot unbox to a native string

./perl6-j --ll-exception -Ilib -e 'use Test'
This type cannot unbox to a native string
  in normalize (gen/jvm/CORE.setting:37671)
  in  (gen/jvm/CORE.setting:37679)
    in setup-repositories (gen/jvm/CORE.setting:37678)
  in  (gen/jvm/CORE.setting:38890)
  in INITIALIZE-DYNAMIC (gen/jvm/CORE.setting:3555)
  in  (gen/jvm/CORE.setting:570)
  in  (gen/jvm/CORE.setting:568)
  in DYNAMIC (gen/jvm/CORE.setting:562)
  in head (gen/jvm/CORE.setting:37757)
  in load_module (src/Perl6/World.nqp:1190)
  in do_pragma_or_load_module (src/Perl6/World.nqp:1120)
  in statement_control:sym<use> (src/Perl6/Grammar.nqp:1549)
  in !protoregex (gen/jvm/stage2/QRegex.nqp:1379)
  in statement_control (src/Perl6/Grammar.nqp)
  in statement (src/Perl6/Grammar.nqp:1244)
  in statementlist (src/Perl6/Grammar.nqp:1173)
  in LANG (gen/jvm/stage2/NQPHLL.nqp:785)
  in FOREIGN_LANG (src/Perl6/Grammar.nqp:1563)
  in comp_unit (src/Perl6/Grammar.nqp:1157)
  in TOP (src/Perl6/Grammar.nqp:460)
  in parse (gen/jvm/stage2/QRegex.nqp:2093)
  in parse (gen/jvm/stage2/NQPHLL.nqp:1488)
  in compile (gen/jvm/stage2/NQPHLL.nqp:1444)
  in eval (gen/jvm/stage2/NQPHLL.nqp:1180)
  in  (gen/jvm/stage2/NQPHLL.nqp:1288)
  in command_eval (gen/jvm/stage2/NQPHLL.nqp:1285)
  in command_eval (src/Perl6/Compiler.nqp:27)
  in command_line (gen/jvm/stage2/NQPHLL.nqp:1269)
  in MAIN (gen/jvm/main.nqp:37)
  in <mainline> (gen/jvm/main.nqp:33)
  in  (gen/jvm/main.nqp)
  
The problem seems to be in src/core/CompUnit/RepositoryRegistry.pm line 125

nqp::join('#', $parts) 

where $parts is a BOOTArray

diff --git a/src/core/CompUnit/RepositoryRegistry.pm b/src/core/CompUnit/RepositoryRegistry.pm
index 1e02697..d2d747e 100644
--- a/src/core/CompUnit/RepositoryRegistry.pm
+++ b/src/core/CompUnit/RepositoryRegistry.pm
@@ -121,7 +121,7 @@ class CompUnit::RepositoryRegistry {
         sub normalize(\spec){
             my $parts := nqp::split('#', spec);
             my $path := nqp::elems($parts) - 1;
-            nqp::bindpos($parts, $path, $SPEC.canonpath(nqp::atpos($parts, $path)));
+            nqp::bindpos($parts, $path, nqp::unbox_s($SPEC.canonpath(nqp::atpos($parts, $path))));
             nqp::join('#', $parts)
         };

$ ./perl6-j -Ilib -e 'use Test; say 42'
42