diff --git a/README.md b/README.md
index 9f594a3..8f2c9bd 100644
--- a/README.md
+++ b/README.md
@@ -35,14 +35,66 @@ You can easily get started based on that.
 
 For MicroZig internals please see the [Design Document](docs/design.adoc).
 
+## Developing
+
+Right now, the developer experience is not optimal due to 0.11 not really supporting what we're doing at all.
+
+If you want to test your changes, you gotta to the following:
+
+**Step 1:** Create a deployment for local usage:
+
+```sh-session
+[user@host] microzig-monorepo/ $ python3 ./tools/bundle.py --debug
+preparing environment...
+validating packages...
+loaded packages:
+  * microzig-build
+  * examples:microchip/avr
+  * examples:...
+  * microzig-core
+  * microchip/avr
+  * ...
+resolving inner dependencies...
+creating packages...
+bundling microzig-build...
+bundling microzig-core...
+bundling microchip/avr...
+...
+[user@host] microzig-monorepo/ $ 
+```
+
+This command yields output in `./microzig-deploy` that is meant to be fetched via `http://localhost:8080/`.
+
+**Step 2:** To serve the files on this port, you can start a pre-bundled web server:
+
+```sh-session
+[user@host] microzig-monorepo/ $ python3 ./tools/demo-server.py
+...
+```
+
+This way, you spawn a local HTTP server that will serve `./microzig-deploy` on port 8080 on your machine, and you can then
+start fetching packages from this.
+
+Now you can use curl to fetch the packages, or you can just create a local development project.
+
+**Step 3:** You can use the tool `tools/patch-build-zon.py` to patch/upgrade your development project inplace:
+
+```sh-session
+[user@host] microzig-monorepo/ $ python3 ./tools/patch-build-zon.py /tmp/dev-project
+Updating hash of http://localhost:8080/packages/microzig-build.tar.gz to 12200040a36bbbb2fe09809861f565fcda9a10ec3064d70357aa40ad0a61596c16fb
+Updating hash of http://localhost:8080/packages/microzig-core.tar.gz to 122013a37ce9ac295303f26057c203e722b9ceaefa5b4403fe5a18ab065f03079e7d
+Updating hash of http://localhost:8080/packages/board-support/stmicro/stm32.tar.gz to 12207c278b78c5aeb08cd7889647d7d0d9a359cb28fe68105d2e43f85dabb3865981
+[user@host] microzig-monorepo/ $
+```
+
 ## Repository structure
 
-- `build/` contains the build components of MicroZig.
-- `core/` contains the shared components of MicroZig.
-- `board-support/` contains all official board support package.
-- `examples/` contains examples that can be used with the board support packages.
-- `tools/` contains tooling to work *on* MicroZig itself, so deployment, testing, ...
-- `design/` contains images and logos
+* `build/` contains the build components of MicroZig.
+* `core/` contains the shared components of MicroZig.
+* `board-support/` contains all official board support package.
+* `examples/` contains examples that can be used with the board support packages.
+* `tools/` contains tooling to work *on* MicroZig itself, so deployment, testing, ...
+* `design/` contains images and logos
 
 ## Versioning Scheme
 
diff --git a/tools/patch-build-zon.py b/tools/patch-build-zon.py
index 85cc962..6cb0ae7 100755
--- a/tools/patch-build-zon.py
+++ b/tools/patch-build-zon.py
@@ -39,7 +39,7 @@ def main():
         elif stripped.startswith(".hash = \""):
             try:
                 pkg_path = PurePosixPath(last_pkg_url.path)
-                assert pkg_path.suffixes ==  ['.tar', '.gz']
+                assert pkg_path.suffixes[-2:] ==  ['.tar', '.gz']
                 pkg_json_url = urlunparse(
                     # scheme, netloc, url, params, query, fragment
                     (
@@ -58,12 +58,14 @@ def main():
 
                 line_prefix = re.match("^(\s*)", line).group(1)
 
+                print(f"Updating hash of {urlunparse(last_pkg_url)} to {pkg_hash}")
+
                 output_lines.append(f'{line_prefix}.hash = "{pkg_hash}",')
                 last_pkg_url = None 
-                
-
+            except AssertionError:
+                raise 
             except BaseException as ex:
-                print(ex)
+                print(f"error: {type(ex)} {ex}")
                 output_lines.append(line)
         else:
             output_lines.append(line)