--- a/libopkg/opkg_conf.c
+++ b/libopkg/opkg_conf.c
-@@ -58,6 +58,7 @@
- { "noaction", OPKG_OPT_TYPE_BOOL, &_conf.noaction },
+@@ -62,6 +62,7 @@
+ { "download_only", OPKG_OPT_TYPE_BOOL, &_conf.download_only },
{ "nodeps", OPKG_OPT_TYPE_BOOL, &_conf.nodeps },
{ "offline_root", OPKG_OPT_TYPE_STRING, &_conf.offline_root },
+ { "overlay_root", OPKG_OPT_TYPE_STRING, &_conf.overlay_root },
{ "query-all", OPKG_OPT_TYPE_BOOL, &_conf.query_all },
--- a/libopkg/opkg_conf.h
+++ b/libopkg/opkg_conf.h
-@@ -74,6 +74,7 @@
+@@ -76,6 +76,7 @@
int check_signature;
int nodeps; /* do not follow dependences */
char *offline_root;
int noaction;
--- a/libopkg/opkg_install.c
+++ b/libopkg/opkg_install.c
-@@ -194,8 +194,11 @@
+@@ -21,6 +21,7 @@
+ #include <time.h>
+ #include <signal.h>
+ #include <unistd.h>
++#include <sys/stat.h>
+
+ #include "pkg.h"
+ #include "pkg_hash.h"
+@@ -189,13 +190,24 @@
+ verify_pkg_installable(pkg_t *pkg)
+ {
+ unsigned long kbs_available, pkg_size_kbs;
+- char *root_dir;
++ char *root_dir = NULL;
++ struct stat s;
+
if (conf->force_space || pkg->installed_size == 0)
return 0;
- root_dir = pkg->dest ? pkg->dest->root_dir :
- conf->default_dest->root_dir;
-+ root_dir = pkg->dest
-+ ? pkg->dest->root_dir
-+ : conf->overlay_root
-+ ? conf->overlay_root
-+ : conf->default_dest->root_dir;
++ if( pkg->dest )
++ {
++ if( !strcmp(pkg->dest->name, "root") && conf->overlay_root
++ && !stat(conf->overlay_root, &s) && (s.st_mode & S_IFDIR) )
++ root_dir = conf->overlay_root;
++ else
++ root_dir = pkg->dest->root_dir;
++ }
++
++ if( !root_dir )
++ root_dir = conf->default_dest->root_dir;
++
kbs_available = get_available_kbytes(root_dir);
pkg_size_kbs = (pkg->installed_size + 1023)/1024;