readme: improve ordering

Add note about uris list

Author: cirosantilli

README.adoc

@@ -81,26 +81,23 @@ cd linux-kernel-module-cheat
 
 The first configure will take a while (30 minutes to 2 hours) to clone and build, see <<benchmark-builds>> for more details.
 
-It does not work if you just download the `.zip` from GitHub because we use link:.gitmodules[Git submodules], you must clone this repo. `./configure` then fetches only the required submodules for you.
-
-It is super easy to build for different CPU architectures, just use the `--arch` option:
-
-....
-./build-qemu --arch arm && \
-  ./build-buildroot --arch arm && \
-  ./run --arch arm && \
-:;
-....
-
-See also: <<cpu-architecture,CPU architectures>>.
-
 If you don't want to wait, you could also try the following faster but much more limited methods:
 
 * <<prebuilt>>
 * <<host>>
 
 but you will soon find that they are simply not enough if you anywhere near serious about systems programming.
 
+If `./configure` fails with:
+
+....
+E: You must put some 'source' URIs in your sources.list
+....
+
+see this: https://askubuntu.com/questions/496549/error-you-must-put-some-source-uris-in-your-sources-list/857433#857433 I don't know how to automate this step. Why, Ubuntu, why.
+
+It does not work if you just download the `.zip` from GitHub because we use link:.gitmodules[Git submodules], you must clone this repo. `./configure` then fetches only the required submodules for you.
+
 After QEMU opens up, you can start playing with the kernel modules:
 
 ....
@@ -136,6 +133,17 @@ See also: <<quit-qemu-from-text-mode>>.
 
 All available modules can be found in the link:packages/kernel_modules/[`kernel_modules` directory].
 
+It is super easy to build for different CPU architectures, just use the `--arch` option:
+
+....
+./build-qemu --arch arm && \
+  ./build-buildroot --arch arm && \
+  ./run --arch arm && \
+:;
+....
+
+See also: <<cpu-architecture,CPU architectures>>.
+
 I now urge you to read the following sections which contain widely applicable information:
 
 * <<run-command-after-boot>>