doc(build): explanation on git submodules and refactor of sync script

• Explanation on the git submodule commands
• Refactor of scripts

docs/BUILD_IMAGES.md

@@ -32,7 +32,7 @@ Now if you have non-tracked files or modified files within git submodules, this
 
 Use the `--verbose` option to see the execution of each command.
 
-If the synchronization fails, you may need to go into the path of the failing git-submodule(s) and clean the workspace from non-tracked/modified files. And then execute the `./scripts/syncComponents.sh` script aagain.
+If the synchronization fails, you may need to go into the path of the failing git-submodule(s) and clean the workspace from non-tracked/modified files. And then execute the `./scripts/syncComponents.sh` script again.
 
 The 2 most important commands to know are :
 
@@ -154,7 +154,7 @@ We are supporting the following releases:
 * Ubuntu `20.04` or `focal`
 * Ubuntu `22.04` or `jammy`
 
-When building, you can specify which base image to work on (by default it will be `ubuntu:jammy`).
+When building, you can specify which base image to work on (by default it will be `ubuntu:focal`).
 
 You just add the `--build-arg BASE_IMAGE=ubuntu:xxxx` option.