IOS build from source for armv7 fail

Development Platform & Builds Mobile
, , ,
1

I try to build a game for my ipad mini1, so I build from engine source,
and set the engine configure file:

[/Script/IOSRuntimeSettings.IOSRuntimeSettings]
bDevForArmV7=True
bDevForArm64=False
bDevForArmV7S=False
bShipForArmV7=False
bShipForArm64=True
bShipForArmV7S=False

but the build get error:
fatal error: error in backend: Cannot select: 0x7faf8b404490: v4f32 = insert_subvector undef:v4f32, 0x7faf88291d38, Constant:i32<0>