update: specifiy kernel version & update readme

.gitmodules

@@ -1,3 +1,4 @@
 [submodule "linux"]
 	path = linux
 	url = https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
+	branch = linux-6.6.y

README.md

@@ -6,34 +6,17 @@
 sudo apt install qemu-system-x86 grub-pc-bin e2fsprogs
 ```
 
-## Run
+## Build
 
 ```bash
-gcc -static -o init/init init/init.c
+git clone <REPOSITORY_URL>
+cd kernel-study
 
-dd if=/dev/zero of=disk.img bs=1M count=512 status=none
+git submodule update --init --recursive --remote --depth 1
-echo -e "n\np\n1\n2048\n\nw" | fdisk disk.img > /dev/null
-
-dd if=disk.img of=part.img bs=512 skip=2048 status=none
-
-mkfs.ext4 part.img
-debugfs -w -R "mkdir /boot" part.img
-debugfs -w -R "mkdir /boot/grub" part.img
-
-debugfs -w -R "write init/init /init" part.img
-debugfs -w -R "write linux/arch/x86/boot/bzImage /boot/bzImage" part.img
-debugfs -w -R "write grub/grub.cfg /boot/grub/grub.cfg" part.img
-
-dd if=part.img of=disk.img bs=512 seek=2048 conv=notrunc status=none
-
-```
-
-Or, alternatively
-
-```bash
 make
 ```
 
+
 ## disk.img structure
 ### 1. 디스크 전체 구조도 (Overview)
 
@@ -119,7 +102,7 @@ Sec 0      Sec 1             Sec 2048                 Sec 526336           Sec 7
 | **Free** | 788480 | 403,701,760 | 127 MB | (사용 안 함) |
 
 
-# `make run`
+## `make run`
 
 ```bash
 ifconfig eth0 10.0.2.15
@@ -133,4 +116,35 @@ Host: 1.1.1.1
 :q
 
 nc 1.1.1.1 80 < req.txt
-```
+```
+
+
+
+## Legacy
+### Run
+
+```bash
+gcc -static -o init/init init/init.c
+
+dd if=/dev/zero of=disk.img bs=1M count=512 status=none
+echo -e "n\np\n1\n2048\n\nw" | fdisk disk.img > /dev/null
+
+dd if=disk.img of=part.img bs=512 skip=2048 status=none
+
+mkfs.ext4 part.img
+debugfs -w -R "mkdir /boot" part.img
+debugfs -w -R "mkdir /boot/grub" part.img
+
+debugfs -w -R "write init/init /init" part.img
+debugfs -w -R "write linux/arch/x86/boot/bzImage /boot/bzImage" part.img
+debugfs -w -R "write grub/grub.cfg /boot/grub/grub.cfg" part.img
+
+dd if=part.img of=disk.img bs=512 seek=2048 conv=notrunc status=none
+
+```
+
+Or, alternatively
+
+```bash
+make
+```