Install ArchLinux on Old ASUS A3000 Laptop

My old ASUS A3 laptop is bought at 2004. It CPU is Intel Celeron 1.33GHz, 490MB memory.

Download install media: archlinux-2014.04.01-dual.iso;
Write this ISO to USB stick with YUMI;
Plugin a usb-netcard (because the netcard of A3000 doesn't work) and startup A3000 with this USB key;
When "Boot> " appeared, press , then input "pxe", then press again, input "nohave64";
After ArchLinux i686 startup, setup ADSL connection with pppoe-setup (I install ArchLinux at home via ADSL):

NIC: enp0s29f7u2 Username: 100002172688 Password: k4... DNS: server

and use default values for other items.

Install arch system. After setup hostname:

pacman -S rp-pppoe openssh grub grub-install --target=i386-pc --recheck /dev/sda
Shutdown system, unpluged USB key, restart system. A "GRUB load failed... no such partition..." error raise
Install arch system. After setup hostname:

pacman -S rp-pppoe openssh grub grub-install --target=i386-pc --recheck /dev/sda
Using USB wireless card to replace USB wired netcard: pacman -S iw gnome-keyring. The USB wireless card is TP-LINK TL_WN725N, bought at jd.com 2013.2.18.
Install video driver: the video card is Intel checked by lspci|grep VGA, so pacman -S xf86-video-intel;
Config SSH servive: systemctl enable sshd;
Shutdown system, unplug USB key, restart system. A "GRUB load failed... no such partition..." error raise.
List partition UUID with blkid, compare them with that in /boot/grub/grub.cfg. They dismatch.
Startup system with USB key. After arch-chroot, run grub-mkconfig -o /boot/grub/grub.cfg to rebuild grub file;
Restart laptop. Arch load successfully.