docs/development/qemu: add details on how to build from source

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>

docs/development/qemu.md

@@ -7,7 +7,75 @@ QEMU is only available for STM32 targets
 ## Getting QEMU
 
 The same QEMU binary found in the SDK can be used to build and develop the firmware.
-If you're using an Apple Silicon Mac, you might find it easier to build QEMU from [source](https://github.com/pebble-dev/qemu).
+Below you can also find a detailed guide on how to build it from source if you need to do so (e.g. on Apple Silicon).
+
+### Building from source
+
+1. Install OS-level pre-requisites:
+
+:::::{tab-set}
+:sync-group: os
+
+::::{tab-item} Ubuntu 24.04 LTS
+:sync: ubuntu
+
+```shell
+sudo apt install autoconf libglib2.0-dev libpixman-1-dev
+```
+
+::::
+
+::::{tab-item} macOS
+:sync: macos
+
+```shell
+brew install autoconf glib pixmap
+```
+
+::::
+:::::
+
+2. Install `pyenv` following [this guide](https://github.com/pyenv/pyenv?tab=readme-ov-file#installation) (steps A-D).
+3. Install Python 2.7:
+
+```shell
+pyenv install 2.7
+```
+
+4. Activate Python 2.7 on the current shell:
+
+```shell
+pyenv local 2.7
+```
+
+5. Clone QEMU
+
+```shell
+git clone --recurse-submodules https://github.com/pebble-dev/qemu
+cd qemu
+```
+
+6. Configure QEMU:
+
+```shell
+./configure \
+  --disable-werror \
+  --enable-debug \
+  --target-list="arm-softmmu" \
+  --extra-cflags=-DSTM32_UART_NO_BAUD_DELAY
+```
+
+7. Build QEMU:
+
+```shell
+make
+```
+
+8. Make sure to make it available on your `PATH`:
+
+```shell
+export PATH=$PWD/arm-softmmu:$PATH
+```
 
 ## Build