Some Macbook EFIs giving me trouble

I'm trying to remove the passwords on several Macbooks. So far I've successfully removed a password on a 2012 MBA, a 2013 MBA, a 2014 MBP and a couple of 2015 MBPs. I have several more 2015s and one more 2014 that just won't work. I've got an EFI Destroyer lite and CH341a programmer with a logic board debug connector. With the MB's I haven't been able to do yet, the CH341a is able to read the chips, but I'm unsuccessful with writing. The EFI Destroyer attempts to program but then fails with a flashing red light. A couple of the MBPs came up as unbootable after I attempted writing (luckily I saved the firmware dumps so hopefully I'll be able to bring them back to life). I've tried the different combinations of now power, battery power, line power, and both. It's especially interesting that the procedure worked with some Macbooks, but not with others that are theoretically identical.

Any ideas what else  I can try? Anyone ever have problems like this?