本にある通り
$ cd ~/workspace/mikanos
$ git checkout osbook_day02a
$ cd ~/edk2
$ ln -s ~/workspace/mikanos/MikanLoaderPkg ./
$ source edksetup.sh
$ build

Conf/target.txt を「表 2.1」に変更しなければならない?
すると今度は…
build.py...
/home/iwao/edk2/MikanLoaderPkg/MikanLoaderPkg.dsc(...): error 4000: Instance of library class [RegisterFilterLib] is not found
in [/home/iwao/edk2/MdePkg/Library/BaseLib/BaseLib.inf] [X64]
consumed by module [/home/iwao/edk2/MikanLoaderPkg/Loader.inf]
![第 2 章 error 4000 Instance of library class [RegisterFilterLib] is not foud](https://i0.wp.com/dev.mish.work/wordpress/wp-content/uploads/2023/06/OSFZ_day02a_error_4000.png?resize=880%2C539&ssl=1)
「error 4000: Instance of library class [RegisterFilterLib] is not found」で検索すると
FAQ(よくある質問とその回答)
次の方法で対応.
$ git checkout 38c8be123aced4cc8ad5c7e0da9121a181b94251
うまくビルドできた.

$ cd ~/workspace/mikanos/
$ git checkout osbook_day02b
$ cd ~/edk2/
$ source edksetup.sh
$ build
$ cd Build/MikanLoaderX64/DEBUG_CLANG38/X64/
$ ~/osbook/devenv/run_qemu.sh ./Loader.efi

