MZ604 - Apparent perfect root installation process but no root !!!

[vronp]

Hi All,

Looking for a suggestion here. I have an MZ604 that has been sitting in my drawer. I eventually want to install a BigPart rom but I'm just getting started here. I've taken the following steps:

1) Unlocked bootloader. This went flawlessly.

2) Installed TWRPv2.8.0.0-Wingray-Non-BigPart on my Xoom. This went flawlessly.

3) Booted into recover and used TWRP to install "vanilla" Xoom-Universal-Root.zip. This also appeared to go flawlessly.

However, various root checker apps tell me I do NOT have root.

Please, any suggestions?

thanks,
Dave