page fault on virtual bus

Hello Hackers,


i try to access some peripheral on my platform. But i get page faults 
when writing to the peripheral at 0x41220000:

MOE: Hello world
MOE: found 505476 KByte free memory
MOE: found RAM from 6f000 to 1f000000
MOE: allocated 495 KByte for the page array @0x9f000
MOE: virtual user address space [0-bfffffff]
MOE: rom name space cap -> [C:501000]
   BOOTFS: [116d000-116d117] [C:503000] periTest.cfg
   BOOTFS: [116e000-116e1aa] [C:504000] periTest.io
   BOOTFS: [116f000-1188494] [C:505000] l4re
   BOOTFS: [1189000-129673c] [C:506000] io
   BOOTFS: [1100000-1152c0c] [C:507000] ned
   BOOTFS: [1153000-116c5e4] [C:508000] periTest
MOE: cmdline: moe rom/periTest.cfg
MOE: Starting: rom/ned rom/periTest.cfg
MOE: loading 'rom/ned'
Ned says: Hi World!
Ned: loading file: 'rom/periTest.cfg'

periTest| L4Re[rm]: unhandled write page fault @41220000 pc=1000294
periTest| L4Re: unhandled exception: pc=0x1000294


Here is my CFG. My io-file looks like the one here 
https://os.inf.tu-dresden.de/L4Re/doc/io.html

## cfg
require("L4");

local loader = L4.default_loader;

local io_buses =
   {
     FOODEVICE = loader:new_channel();
   };

loader:start({
   caps ={
     FOODEVICE = io_buses.FOODEVICE:svr(),
   },
},
  "rom/periTest rom/periTest.io"
);
## end CFG


Thanks for any help.