[seL4] libsel4cspace and IPC

Hi, I'm trying to implement a "create endpoint" syscall as a continuation of my AOS project last year. I'm using the following code to create and endpoint in the current threads's cspace (using libsel4cspace): https://gist.github.com/anonymous/8294aa47ad351e4d4066 When this code runs, seL4 prints the following during the cspace_ut_retype_addr call: <> This error comes from inside libsel4cspace, specifically where it calls seL4_Untyped_RetypeAtOffset(). I've read the libsel4cspace documentation and enabled CSPACE_DEBUG, but nothing from the output looks amiss (I'm not an expert though, and I can post the relevant debug output). Have I done anything wrong in the code above? Thanks, - Will