Added instructions for Arch Linux (#3)

README.md

@@ -32,6 +32,46 @@ sudo cp /boot/initrd.img-$(uname -r) /boot/efi/initrd.img
 
 If you are updating Linux on your M.2 SSD, but you do not directly boot into it, i.e. if you use `m2_exec.sh`, then you do need to do this step.
 
+## Compilation and Installation (Arch Linux)
+
+Since Arch Linux is different on how the kernel is built, here are some updated commands for compiling
+```bash
+git clone https://github.com/ps5-linux/ps5-linux-patches
+git clone https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
+cd linux
+git checkout tags/v7.0.3
+git apply ../ps5-linux-patches/linux.patch
+cp ../ps5-linux-patches/.config .config
+make olddefconfig
+make -j$(nproc)
+```
+
+In the same `linux` folder after compilation, do:
+
+```bash
+sudo make modules_install
+sudo make install
+```
+
+Then generate the initrd:
+
+```bash
+sudo mkinitcpio -k "$(make kernelrelease)" -g /boot/initrd.img-$(make kernelrelease) || true
+```
+
+If you are updating Linux on your external USB SSD or you are directly booting into M.2 SSD, i.e. you use `-m2` in `cmdline.txt`, then you have to update the files on the FAT32 partition of your USB drive:
+
+```bash
+sudo mv /boot/efi/bzImage /boot/efi/bzImage.old
+sudo mv /boot/efi/initrd.img /boot/efi/initrd.img.old
+sudo cp ~/linux/arch/x86/boot/bzImage /boot/efi/bzImage
+sudo cp /boot/initrd.img-$(make kernelrelease) /boot/efi/initrd.img
+sync
+```
+
+If you are updating Linux on your M.2 SSD, but you do not directly boot into it, i.e. if you use `m2_exec.sh`, then you do not need to do this step.
+
+
 ## TODO
 
 - amdgpu smu driver to show correct gpu frequency and temperature