userboot_getdev
(void) userboot_getdev((void **)(&rootdev), rootdevname, NULL);
(void) userboot_getdev(NULL, kernelname, &kernelpath);
(void) userboot_getdev((void **)(&rootdev), rootdevname, NULL);
extern int userboot_getdev(void **, const char *, const char **);
archsw.arch_getdev = userboot_getdev;