Can't restore backup from ext SD card

Hi

I created a backup at my external SD before flashing a custom ROM
i followed the guide on how to install the rom but i got status 7 error

and i decided to restore my backup but
i suddenly got this error at my CWM

Quote:

Checking MD5 sums. . . No MD5 verification performed Erasing boot image. . . Restoring system. . . Error while restoring /system!

i have this option before the error

Quote:

Could not find reference MD5 for: boot.img system.ext4.tar system.ext4.tar.a system.ext4.tar.b Continue anyways? yes? or no?

my phone is Honor 6, H60-L04
cwm v6.0.5.0