I found solution here: https://wiki.archlinux.org/index.php/ASUS_Eee_PC_T101MT#Brightness
Type: Posts; User: Malexan; Keyword(s):
I found solution here: https://wiki.archlinux.org/index.php/ASUS_Eee_PC_T101MT#Brightness
TrueCrypt bootloader has to be installed in MBR. GRUB2 works unstable when it's installed in a partition but not in MBR. I've downgraded to GRUB Legacy and now it works.