diff --git a/README.md b/README.md
index 48196459..bb387bc7 100644
--- a/README.md
+++ b/README.md
@@ -1569,10 +1569,12 @@ interact with copyparty using non-browser clients
   * `var xhr = new XMLHttpRequest(); xhr.open('POST', '//127.0.0.1:3923/msgs?raw'); xhr.send('foo');`
 
 * curl/wget: upload some files (post=file, chunk=stdin)
-  * `post(){ curl -F act=bput -F f=@"$1" http://127.0.0.1:3923/?pw=wark;}`  
-    `post movie.mkv`
+  * `post(){ curl -F f=@"$1" http://127.0.0.1:3923/?pw=wark;}`  
+    `post movie.mkv`  (gives HTML in return)
+  * `post(){ curl -F f=@"$1" 'http://127.0.0.1:3923/?want=url&pw=wark';}`  
+    `post movie.mkv`  (gives hotlink in return)
   * `post(){ curl -H pw:wark -H rand:8 -T "$1" http://127.0.0.1:3923/;}`  
-    `post movie.mkv`
+    `post movie.mkv`  (randomized filename)
   * `post(){ wget --header='pw: wark' --post-file="$1" -O- http://127.0.0.1:3923/?raw;}`  
     `post movie.mkv`
   * `chunk(){ curl -H pw:wark -T- http://127.0.0.1:3923/;}`  
diff --git a/copyparty/httpcli.py b/copyparty/httpcli.py
index 287c64ca..816ac69b 100644
--- a/copyparty/httpcli.py
+++ b/copyparty/httpcli.py
@@ -45,6 +45,7 @@ from .util import (
     ODict,
     Pebkac,
     UnrecvEOF,
+    WrongPostKey,
     absreal,
     alltrace,
     atomic_move,
@@ -1862,7 +1863,16 @@ class HttpCli(object):
         self.parser = MultipartParser(self.log, self.sr, self.headers)
         self.parser.parse()
 
-        act = self.parser.require("act", 64)
+        file0: list[tuple[str, Optional[str], Generator[bytes, None, None]]] = []
+        try:
+            act = self.parser.require("act", 64)
+        except WrongPostKey as ex:
+            if ex.got == "f" and ex.fname:
+                self.log("missing 'act', but looks like an upload so assuming that")
+                file0 = [(ex.got, ex.fname, ex.datagen)]
+                act = "bput"
+            else:
+                raise
 
         if act == "login":
             return self.handle_login()
@@ -1875,7 +1885,7 @@ class HttpCli(object):
             return self.handle_new_md()
 
         if act == "bput":
-            return self.handle_plain_upload()
+            return self.handle_plain_upload(file0)
 
         if act == "tput":
             return self.handle_text_upload()
@@ -2314,7 +2324,9 @@ class HttpCli(object):
             vfs.flags.get("xau") or [],
         )
 
-    def handle_plain_upload(self) -> bool:
+    def handle_plain_upload(
+        self, file0: list[tuple[str, Optional[str], Generator[bytes, None, None]]]
+    ) -> bool:
         assert self.parser
         nullwrite = self.args.nw
         vfs, rem = self.asrv.vfs.get(self.vpath, self.uname, False, True)
@@ -2340,7 +2352,8 @@ class HttpCli(object):
         t0 = time.time()
         try:
             assert self.parser.gen
-            for nfile, (p_field, p_file, p_data) in enumerate(self.parser.gen):
+            gens = itertools.chain(file0, self.parser.gen)
+            for nfile, (p_field, p_file, p_data) in enumerate(gens):
                 if not p_file:
                     self.log("discarding incoming file without filename")
                     # fallthrough
diff --git a/copyparty/util.py b/copyparty/util.py
index b97f514c..8a7e5beb 100644
--- a/copyparty/util.py
+++ b/copyparty/util.py
@@ -1537,11 +1537,9 @@ class MultipartParser(object):
         raises if the field name is not as expected
         """
         assert self.gen
-        p_field, _, p_data = next(self.gen)
+        p_field, p_fname, p_data = next(self.gen)
         if p_field != field_name:
-            raise Pebkac(
-                422, 'expected field "{}", got "{}"'.format(field_name, p_field)
-            )
+            raise WrongPostKey(field_name, p_field, p_fname, p_data)
 
         return self._read_value(p_data, max_len).decode("utf-8", "surrogateescape")
 
@@ -3058,3 +3056,20 @@ class Pebkac(Exception):
 
     def __repr__(self) -> str:
         return "Pebkac({}, {})".format(self.code, repr(self.args))
+
+
+class WrongPostKey(Pebkac):
+    def __init__(
+        self,
+        expected: str,
+        got: str,
+        fname: Optional[str],
+        datagen: Generator[bytes, None, None],
+    ) -> None:
+        msg = 'expected field "{}", got "{}"'.format(expected, got)
+        super(WrongPostKey, self).__init__(422, msg)
+
+        self.expected = expected
+        self.got = got
+        self.fname = fname
+        self.datagen = datagen
diff --git a/docs/devnotes.md b/docs/devnotes.md
index 3eeb6027..10ac2a86 100644
--- a/docs/devnotes.md
+++ b/docs/devnotes.md
@@ -162,8 +162,8 @@ authenticate using header `Cookie: cppwd=foo` or url param `&pw=foo`
 | PUT | | (binary data) | upload into file at URL |
 | PUT | `?gz` | (binary data) | compress with gzip and write into file at URL |
 | PUT | `?xz` | (binary data) | compress with xz and write into file at URL |
-| mPOST | | `act=bput`, `f=FILE` | upload `FILE` into the folder at URL |
-| mPOST | `?j` | `act=bput`, `f=FILE` | ...and reply with json |
+| mPOST | | `f=FILE` | upload `FILE` into the folder at URL |
+| mPOST | `?j` | `f=FILE` | ...and reply with json |
 | mPOST | | `act=mkdir`, `name=foo` | create directory `foo` at URL |
 | POST | `?delete` | | delete URL recursively |
 | jPOST | `?delete` | `["/foo","/bar"]` | delete `/foo` and `/bar` recursively |