Yes, actually the On5 came originally with Marshmallows. There is Lollipop version for this phone to my understanding.
Did you flashed all the files correctly on every BL, AP, CSC, and so on? I so, try only flashing AP, Modem, and CSC only. Just do not do the bootloader BL
I lined up all the correct files in Odin, spent like 3 hours last night trying to figure it out what I was doing wrong. Im about to give it another try right now, Im going to post all the errors I get on the phone and from Odin to see if you or someone else can figure out what is wrong.
So, when I flash the bootloader, everything works. It flashes and reboots to the FRP lock boot screen with no errors.
When I try and flash the AP file I get an error almost immediately, Phone says that its blocked because of FRP Custom Binary(BOOT) Blocked by FRP Lock
When I try and flash the modem or CP, it gets about 3 quarters of the way and stops at the writing process, odin says fail and the phone says there's an issue with the radio, SECURE CHECK FAIL (RADIO)
The firmware I downloaded also doesn't have a CSC file on it, it has something else called OPT_G550TUVU1APF1.tar.md5 , is that the CSC file? but if it is it doesn't work anyways, almost fails immediately in Odin with no error message on the phone but odin says Complete(Write)Operation failed.
Also when I flash the PIT file, odin says Re-Partition Operation failed. On the phone it says SECURE CHECK FAIL (PIT)
On Odin 3.12
Thats pretty much all the info I've gotten from everything, hopefully someone can help, been trying to figure this out for like a week straight searching all over this forum and youtube trying my best but **** doesnt wanna go my way.