diff --git a/source/src/audiomanager.cpp b/source/src/audiomanager.cpp
index d0c70af6..cefb2800 100644
--- a/source/src/audiomanager.cpp
+++ b/source/src/audiomanager.cpp
@@ -923,6 +923,7 @@ void getmapsoundorigin(char *fname)
     const char *res = s;
     switch(findfilelocation)
     {
+        case FFL_ZIP:     res = "zip";                                                break;
         case FFL_WORKDIR: res = fileexists(s, "r") ? "official" : "<file not found>"; break;
         case FFL_HOME:    res = "custom";                                             break;
         default:          formatstring(s)("package dir #%d", findfilelocation);       break;
diff --git a/source/src/client.cpp b/source/src/client.cpp
index d60c459a..6f6c00c6 100644
--- a/source/src/client.cpp
+++ b/source/src/client.cpp
@@ -1033,7 +1033,7 @@ int processdownload(package *pck)
 
             case PCK_MAP: case PCK_MAPMODEL:
             {
-                addzip("tmp", pck->name, NULL, true, pck->type);
+//                addzip("tmp", pck->name, NULL, true, pck->type);
                 break;
             }
 
@@ -1041,7 +1041,7 @@ int processdownload(package *pck)
             {
                 char *fname = newstring(pck->name), *ls = strrchr(fname, '/');
                 if(ls) *ls = '\0';
-                addzip("tmp", fname, NULL, true, pck->type);
+//                addzip("tmp", fname, NULL, true, pck->type);
                 rereadtexturelists = 1;
                 break;
             }
diff --git a/source/src/clients2c.cpp b/source/src/clients2c.cpp
index 97426c3e..6fdd518a 100644
--- a/source/src/clients2c.cpp
+++ b/source/src/clients2c.cpp
@@ -1468,7 +1468,7 @@ void receivefile(uchar *data, int len)
                 break;
             }
             path(fname);
-            stream *demo = openrawfile(fname, "wb");
+            stream *demo = openfile(fname, "wb");
             if(!demo)
             {
                 conoutf("failed writing to \"%s\"", fname);
diff --git a/source/src/command.cpp b/source/src/command.cpp
index c869ccaf..84e8753d 100644
--- a/source/src/command.cpp
+++ b/source/src/command.cpp
@@ -1616,7 +1616,7 @@ void deletecfg()
         loopi(sizeof(configs)/sizeof(configs[0]))
         {
             const char *file = findfile(path(configs[i], true), "r");
-            if(!file) continue;
+            if(!file || findfilelocation == FFL_ZIP) continue;
             delfile(file);
         }
     }
diff --git a/source/src/main.cpp b/source/src/main.cpp
index b1dea776..696e0432 100644
--- a/source/src/main.cpp
+++ b/source/src/main.cpp
@@ -146,6 +146,8 @@ void writeinitcfg()
     f->printf("audio %d\n", audio > 0 ? 1 : 0);
     f->printf("soundchannels %d\n", soundchannels);
     if(lang && *lang) f->printf("lang %s\n", lang);
+    extern void writezipmodconfig(stream *f);
+    writezipmodconfig(f);
     delete f;
 }
 
@@ -941,6 +943,7 @@ void autostartscripts(const char *prefix)
 
 void createconfigtemplates(const char *templatezip)  // create customisable config files in homedir - only if missing
 {
+#if 0
     if(addzip(templatezip))
     {
         vector<char *> files;
@@ -971,6 +974,7 @@ void createconfigtemplates(const char *templatezip)  // create customisable conf
         removezip(templatezip);
     }
     findfile(AUTOSTARTPATH "dummy", "w"); // create empty autostart directory, if it doesn't exist yet
+#endif
 }
 
 extern void connectserv(char *, int *, char *);
diff --git a/source/src/stream.cpp b/source/src/stream.cpp
index c87b66f6..9ffd3819 100644
--- a/source/src/stream.cpp
+++ b/source/src/stream.cpp
@@ -241,6 +241,11 @@ const char *findfile(const char *filename, const char *mode)
         }
         return s;
     }
+    findfilelocation = FFL_ZIP;
+#ifndef STANDALONE
+    formatstring(s)("zip://%s", filename);
+    if(findzipfile(filename)) return s;
+#endif
     loopv(packagedirs)
     {
         findfilelocation++;
@@ -290,25 +295,23 @@ bool listdir(const char *dir, const char *ext, vector<char *> &files)
     else return false;
 }
 
-int listfiles(const char *dir, const char *ext, vector<char *> &files)
+void listfiles(const char *dir, const char *ext, vector<char *> &files)
 {
-    int dirs = 0;
-    if(listdir(dir, ext, files)) dirs++;
+    listdir(dir, ext, files);
     string s;
     if(homedir[0])
     {
         formatstring(s)("%s%s", homedir, dir);
-        if(listdir(s, ext, files)) dirs++;
+        listdir(s, ext, files);
     }
     loopv(packagedirs)
     {
         formatstring(s)("%s%s", packagedirs[i], dir);
-        if(listdir(s, ext, files)) dirs++;
+        listdir(s, ext, files);
     }
 #ifndef STANDALONE
-    dirs += listzipfiles(dir, ext, files);
+    listzipfiles(dir, ext, files);
 #endif
-    return dirs;
 }
 
 #ifndef STANDALONE
@@ -332,7 +335,7 @@ void listfilesrecursive(const char *dir, vector<char *> &files, int level)
 
 bool delfile(const char *path)
 {
-    return !remove(path);
+    return strncmp(path, "zip://", 6) ? !remove(path) : false;
 }
 
 void backup(char *name, char *backupname)
@@ -885,13 +888,12 @@ stream *openmemfile(const uchar *buf, int size, int *refcnt)
 
 stream *openrawfile(const char *filename, const char *mode)
 {
-    const char *found = findfile(filename, mode);
 #ifndef STANDALONE
-    if(mode && (mode[0]=='w' || mode[0]=='a')) conoutf("writing to file: %s", found);
+    if(mode && (mode[0]=='w' || mode[0]=='a')) conoutf("writing to file: %s", filename);
 #endif
-    if(!found) return NULL;
+    if(!strncmp(filename, "zip://", 6)) return NULL;
     filestream *file = new filestream;
-    if(!file->open(found, mode))
+    if(!file->open(filename, mode))
     {
 #ifndef STANDALONE
 //         conoutf("file failure! %s",filename);
@@ -903,11 +905,11 @@ stream *openrawfile(const char *filename, const char *mode)
 
 stream *openfile(const char *filename, const char *mode)
 {
+    const char *found = findfile(filename, mode);
 #ifndef STANDALONE
-    stream *s = openzipfile(filename, mode);
-    if(s) return s;
+    if(!strncmp(found, "zip://", 6)) return openzipfile(found + 6, mode);
 #endif
-    return openrawfile(filename, mode);
+    return openrawfile(found, mode);
 }
 
 int getfilesize(const char *filename)
diff --git a/source/src/texture.cpp b/source/src/texture.cpp
index 50dd39a1..dc80a363 100644
--- a/source/src/texture.cpp
+++ b/source/src/texture.cpp
@@ -366,18 +366,22 @@ GLuint loadsurface(const char *texname, int &xs, int &ys, int &bpp, int clamp =
     }
 
     SDL_Surface *s = NULL;
-    stream *z = openzipfile(file, "rb");
-    if(z)
+    const char *ffile = findfile(file, "rb");
+    if(findfilelocation == FFL_ZIP)
     {
-        SDL_RWops *rw = z->rwops();
-        if(rw)
+        stream *z = openzipfile(file, "rb");
+        if(z)
         {
-            s = IMG_Load_RW(rw, 0);
-            SDL_FreeRW(rw);
+            SDL_RWops *rw = z->rwops();
+            if(rw)
+            {
+                s = IMG_Load_RW(rw, 0);
+                SDL_FreeRW(rw);
+            }
+            delete z;
         }
-        delete z;
     }
-    if(!s) s = IMG_Load(findfile(file, "rb"));
+    else if(!s) s = IMG_Load(ffile);
     if(!s)
     {
         if(trydl)
@@ -1080,6 +1084,7 @@ void gettextureorigin(char *fname)
     const char *res = s;
     switch(findfilelocation)
     {
+        case FFL_ZIP:     res = "zip";                                                break;
         case FFL_WORKDIR: res = fileexists(s, "r") ? "official" : "<file not found>"; break;
         case FFL_HOME:    res = "custom";                                             break;
         default:          formatstring(s)("package dir #%d", findfilelocation);       break;
diff --git a/source/src/tools.h b/source/src/tools.h
index e5eaa73c..489eec3d 100644
--- a/source/src/tools.h
+++ b/source/src/tools.h
@@ -944,12 +944,12 @@ extern size_t fixpackagedir(char *dir);
 extern void sethomedir(const char *dir);
 extern void addpackagedir(const char *dir);
 extern int findfilelocation;
-enum { FFL_WORKDIR = -1, FFL_HOME = 0 };
+enum { FFL_WORKDIR = -2, FFL_HOME = -1, FFL_ZIP = 0 };
 extern const char *findfile(const char *filename, const char *mode);
 extern int getfilesize(const char *filename);
 extern stream *openvecfile(vector<uchar> *s = NULL);
 extern stream *openmemfile(const uchar *buf, int size, int *refcnt);
-extern stream *openrawfile(const char *filename, const char *mode);
+extern bool findzipfile(const char *name);
 extern stream *openzipfile(const char *filename, const char *mode);
 extern stream *openfile(const char *filename, const char *mode);
 extern stream *opentempfile(const char *filename, const char *mode);
@@ -957,13 +957,11 @@ extern stream *opengzfile(const char *filename, const char *mode, stream *file =
 extern char *loadfile(const char *fn, int *size, const char *mode = NULL);
 extern void filerotate(const char *basename, const char *ext, int keepold, const char *oldformat = NULL);
 extern bool listdir(const char *dir, const char *ext, vector<char *> &files);
-extern int listfiles(const char *dir, const char *ext, vector<char *> &files);
+extern void listfiles(const char *dir, const char *ext, vector<char *> &files);
 extern void listfilesrecursive(const char *dir, vector<char *> &files, int level = 0);
-extern int listzipfiles(const char *dir, const char *ext, vector<char *> &files);
+extern void listzipfiles(const char *dir, const char *ext, vector<char *> &files);
 extern bool delfile(const char *path);
 extern void backup(char *name, char *backupname);
-extern bool addzip(const char *name, const char *mount = NULL, const char *strip = NULL, bool extract = false, int type = -1);
-extern bool removezip(const char *name);
 extern struct mapstats *loadmapstats(const char *filename, bool getlayout);
 extern bool cmpb(void *b, int n, enet_uint32 c);
 extern bool cmpf(char *fn, enet_uint32 c);
diff --git a/source/src/zip.cpp b/source/src/zip.cpp
index fbec80e6..5a288a38 100644
--- a/source/src/zip.cpp
+++ b/source/src/zip.cpp
@@ -44,35 +44,24 @@ struct ziparchive;
 
 struct zipfile // file in a zip archive
 {
-    char *name;
+    char *name, *fullname; // name from zip, full path name
     uint header, offset, size, compressedsize;
+    ziparchive *location;
 
-    zipfile() : name(NULL), header(0), offset(~0U), size(0), compressedsize(0)
-    {
-    }
-    ~zipfile()
-    {
-        DELETEA(name);
-    }
+    zipfile() : name(NULL), fullname(NULL), header(0), offset(~0U), size(0), compressedsize(0), location(NULL) { }
+    ~zipfile() { DELSTRING(name); DELSTRING(fullname); }
 };
 
 struct ziparchive // zip archive file
 {
     char *name;
-    hashtable<const char *, zipfile> files;
     stream *data;
+    vector<zipfile> files;
     int openfiles;
-    int type;
     zipstream *owner;
 
-    ziparchive() : name(NULL), files(512), data(NULL), openfiles(0), type(-1), owner(NULL)
-    {
-    }
-    ~ziparchive()
-    {
-        DELETEA(name);
-        DELETEP(data);
-    }
+    ziparchive() : name(NULL), data(NULL), openfiles(0), owner(NULL) { }
+    ~ziparchive() { DELSTRING(name); DELETEP(data); }
 };
 
 static bool findzipdirectory(stream *f, zipdirectoryheader &hdr)
@@ -195,8 +184,7 @@ static bool readlocalfileheader(stream *f, ziplocalfileheader &h, uint offset)
     return true;
 }
 
-static vector<ziparchive *> archives;
-
+#if 0
 ziparchive *findzip(const char *name)
 {
     loopv(archives) if(!strcmp(name, archives[i]->name)) return archives[i];
@@ -355,6 +343,9 @@ bool removezip(const char *name)
     delete exists;
     return true;
 }
+#endif
+
+// stream interface
 
 struct zipstream : stream
 {
@@ -554,68 +545,178 @@ struct zipstream : stream
     }
 };
 
-bool extractzipfile(ziparchive *a, zipfile *f, const char *name)
+// manage zips as part of the AC virtual filesystem
+
+static vector<ziparchive *> archives; // list of mounted zip files, highest priority first
+static hashtable<const char *, zipfile *> zipfiles; // table of all files in all mounted zips
+
+static void mountzip(ziparchive &arch, const char *mountdir, const char *stripdir, bool allowconfig)
 {
-    zipstream *s = new zipstream;
-    FILE *target = NULL;
-    defformatstring(fname)("%s", findfile(name, "wb"));
-    bool error = false;
-    if(s->open(a, f) && (target = fopen(fname, "wb")))
+    string mdir = "", fname;
+    if(mountdir)
     {
-        size_t len;
-        uchar copybuf[1024];
-        while((len = s->read(copybuf, 1024))) fwrite(copybuf, 1, len, target);
+        copystring(mdir, mountdir);
+        if(fixpackagedir(mdir) <= 1) mdir[0] = '\0';
     }
-    else error = true;
-    if(error) conoutf("failed to extract zip file %s from archive %s", fname, a->name);
-    if(target) fclose(target);
-    delete s;
-    return !error;
+    int striplen = stripdir ? (int)strlen(stripdir) : 0;
+
+    loopv(arch.files)
+    { // build full path names - and check them
+        zipfile *zf = &arch.files[i];
+        formatstring(fname)("%s%s", mdir, striplen && !strncmp(zf->name, stripdir, striplen) ? zf->name + striplen : zf->name);
+        path(fname);
+        unixpath(fname);
+        zf->fullname = newstring(fname);
+        zf->location = &arch;
+        filtertext(fname, fname, FTXT__MEDIAFILEPATH);
+        if(strcmp(fname, zf->fullname) || (strncmp("packages/", fname, 9) && (!allowconfig || strncmp("config/", fname, 7))))
+        { // path is not allowed (illegal characters or illegal path)
+#if defined(_DEBUG) && !defined(STANDALONE)
+            clientlogf("mountzip: ignored file %s from zip %s", fname, arch.name);
+#endif
+            arch.files.remove(i--).~zipfile();
+        }
+        else path(zf->fullname);
+    }
+}
+
+static void rebuildzipfilehashtable()
+{
+    zipfiles.clear(false);
+    loopv(archives)
+    {
+        ziparchive *arch = archives[i];
+        loopvj(arch->files)
+        {
+            zipfile *zf = &arch->files[j];
+            zipfiles.access(zf->fullname, zf);
+        }
+    }
+}
+
+// manage zipped mod packages in subdirectory "mods/" including description and preview images
+// zip packages are restricted to contain files below "packages/" only - unless the zip filename starts with "###", which additionally allows files below "config/"
+
+ziparchive *findzip(const char *name)
+{
+    loopv(archives) if(!strcmp(name, archives[i]->name)) return archives[i];
+    return NULL;
+}
+
+#ifndef STANDALONE
+
+const char *fixzipname(char *name) // check, if valid path + filename, based on mods/, return NULL if invalid
+{
+    string tmp;
+    unixpath(name); // changes "name"!
+    filtertext(tmp, name, FTXT__MEDIAFILEPATH);
+    const char *bp = behindpath(tmp), *pd = parentdir(tmp);
+    static defformatstring(pname)("%s%s%s%s", pd, bp != tmp ? "/" : "", !strncmp("###", behindpath(name), 3) ? "###" : "", bp);
+    if(strlen(name) > 40 || strchr(name, '.') || strcmp(pname, name) || *name == '/') return NULL; // illegal filename
+    formatstring(pname)("mods/%s.zip", name);
+    return path(pname);
+}
+
+VAR(zipcachemaxsize, 0, 512, 1024); // load zip files smaller than 512K straight into RAM
+
+void addzipmod(char *name)
+{
+    const char *pname = fixzipname(name);
+    if(!pname)
+    {
+        conoutf("addzipmod: illegal filename %s", name);
+        return;
+    }
+    ziparchive *exists = findzip(name);
+    if(exists)
+    { // already added zip
+        archives.removeobj(exists);
+        archives.add(exists); // sort to the end of the list
+        rebuildzipfilehashtable();
+        return;
+    }
+    ziparchive *arch = new ziparchive;
+    arch->name = newstring(name);
+    if(!(arch->data = openfile(pname, "rb")))
+    {
+        conoutf("could not open file %s", pname);
+        delete arch;
+        return;
+    }
+    int zipsize = arch->data->size();
+    if(zipsize > 0 && zipsize < zipcachemaxsize * 1024)
+    {
+        uchar *buf = new uchar[zipsize];
+        if(arch->data->read(buf, zipsize) != zipsize)
+        {
+            conoutf("could not cache file %s", pname);
+            delete[] buf;
+            delete arch;
+            return;
+        }
+        delete arch->data;
+        arch->data = openmemfile(buf, zipsize, NULL);
+    }
+    zipdirectoryheader h;
+    if(!findzipdirectory(arch->data, h) || !readzipdirectory(arch->data, h.entries, h.offset, h.size, arch->files))
+    {
+        conoutf("could not read directory in zip %s", pname);
+        delete arch;
+        return;
+    }
+    mountzip(*arch, NULL, NULL, !strncmp(behindpath(name), "###", 3));
+    archives.add(arch);
+    rebuildzipfilehashtable();
+    clientlogf("added zipmod %s, %d bytes, %d files", pname, zipsize, arch->files.length());
+}
+COMMAND(addzipmod, "s");
+
+void writezipmodconfig(stream *f)
+{
+    f->printf("zipcachemaxsize %d\n", zipcachemaxsize);
+    loopv(archives) f->printf("addzipmod %s\n", archives[i]->name);
+}
+
+#endif
+
+// AC virtual filesystem
+
+bool findzipfile(const char *name)
+{
+    return zipfiles.access(name) != NULL;
 }
 
 stream *openzipfile(const char *name, const char *mode)
 {
     for(; *mode; mode++) if(*mode=='w' || *mode=='a') return NULL;
-    loopvrev(archives)
+//    if(!strncmp(name, "zip://", 6)) name += 6;
+    zipfile **zf = zipfiles.access(name);
+    if(zf && *zf)
     {
-        ziparchive *arch = archives[i];
-        zipfile *f = arch->files.access(name);
-        if(!f) continue;
         zipstream *s = new zipstream;
-        if(s->open(arch, f)) return s;
+        if(s->open((*zf)->location, *zf)) return s;
         delete s;
     }
     return NULL;
 }
 
-int listzipfiles(const char *dir, const char *ext, vector<char *> &files)
+void listzipfiles(const char *dir, const char *ext, vector<char *> &files) // (does not list memfiles)
 {
-    int extsize = ext ? (int)strlen(ext)+1 : 0, dirsize = (int)strlen(dir), dirs = 0;
-    loopvrev(archives)
+    int extsize = ext ? (int)strlen(ext)+1 : 0, dirsize = (int)strlen(dir);
+    enumerate(zipfiles, zipfile *, zf,
     {
-        ziparchive *arch = archives[i];
-        int oldsize = files.length();
-        enumerate(arch->files, zipfile, f,
+        if(strncmp(zf->fullname, dir, dirsize)) continue;
+        const char *name = zf->fullname + dirsize;
+        if(name[0] == PATHDIV) name++;
+        if(strchr(name, PATHDIV)) continue;
+        if(!ext) files.add(newstring(name));
+        else
         {
-            if(strncmp(f.name, dir, dirsize)) continue;
-            const char *name = f.name + dirsize;
-            if(name[0] == PATHDIV) name++;
-            if(strchr(name, PATHDIV)) continue;
-            if(!ext) files.add(newstring(name));
-            else
-            {
-                int namelength = (int)strlen(name) - extsize;
-                if(namelength > 0 && name[namelength] == '.' && strncmp(name+namelength+1, ext, extsize-1)==0)
-                    files.add(newstring(name, namelength));
-            }
-        });
-        if(files.length() > oldsize) dirs++;
-    }
-    return dirs;
+            int namelength = (int)strlen(name) - extsize;
+            if(namelength > 0 && name[namelength] == '.' && strncmp(name+namelength+1, ext, extsize-1)==0)
+                files.add(newstring(name, namelength));
+        }
+    });
 }
 
-#ifndef STANDALONE
-COMMANDF(addzip, "sss", (const char *name, const char *mount, const char *strip) { addzip(name, mount[0] ? mount : NULL, strip[0] ? strip : NULL); });
-COMMANDF(removezip, "s", (const char *name) { removezip(name); });
-#endif