I want to apply some registry tweaks without cmdlines.txt.

Tried to create regtweaks.inf file:

[Version]
Signature = "$Windows NT$"

[DefaultInstall]
DelReg = RT.DelReg
AddReg = RT.AddReg

[RT.AddReg]

HKU,".DEFAULT\Keyboard Layout\Preload,"1",0x00020000,"00000409"
HKU,".DEFAULT\Keyboard Layout\Preload,"2",0x00020000,"00000419"
HKU,".DEFAULT\Keyboard Layout\Toggle,"Hotkey",0x00020000,"2"
HKU,".DEFAULT\Keyboard Layout\Toggle,"Language Hotkey",0x00020000,"2"
HKU,".DEFAULT\Keyboard Layout\Toggle,"Layout Hotkey",0x00020000,"1"


[RT.DelReg]

But setup gives an error message about 10th row of this file.

What is wrong?

well ,without really knowing what you are trying to achieve, a look at the reg file would help confirm it, but the values you are using are of type REG_SZ and should therefore use 0x00000000 not 0x00020000.