diff --git a/README.md b/README.md
index c9b94466..2fe50d3e 100644
--- a/README.md
+++ b/README.md
@@ -1,6 +1,8 @@
 os-tutorial
 ===========
 
+_⚠️ Hey! This is an old, abandoned project, with both technical and design issues [listed here](https://github.com/cfenollosa/os-tutorial/issues/269). Please have fun with this tutorial but do look for more modern and authoritative sources if you want to learn about OS design. ⚠️_
+
 How to create an OS from scratch!
 
 I have always wanted to learn how to make an OS from scratch. In college I was taught
@@ -12,7 +14,7 @@ but:
 - I'm fed up with people who think that reading an already existing kernel, even if small, is 
 a good idea to learn operating systems.
 
-Inspired by [this document](http://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures/os-dev.pdf)
+Inspired by [this document](https://web.archive.org/web/20211008041419/http://www.cs.bham.ac.uk/~exr/lectures/opsys/10_11/lectures/os-dev.pdf)
 and the [OSDev wiki](http://wiki.osdev.org/), I'll try to make short step-by-step READMEs and
 code samples for anybody to follow. Honestly, this tutorial is basically the first document but
 split into smaller pieces and without the theory.