Couple of problems updating

[Kevin Kofler]

Si I have purchased the pro 64 version, don't remember in its explorer pro or what. I have searched for "how to identify" which hardware modle i have but haven't found anything to confirm.

If it is a PinePhone Pro, it is almost certainly the Explorer Edition. There have been no other widely distributed versions yet.

Problem 1. Whenever "power" is connected (Battery or usb) it boots
Problem 2. No matter what I do, I cannot "shut down", it just boots again

That it boots if you newly plug in a power source is considered a feature, not a bug. My original PinePhone also does that. I am not aware of any way to turn that off. But it should not boot just because you have a power source already plugged in.

Problem 3. cant connect adb to device.

That is because the PinePhone does not use adb. (The modem chip does, internally, but that is only relevant if you want to upgrade or replace the modem firmware. The main CPU uses uBoot/Tow-Boot as bootloaders, not fastboot, so it cannot be used with Android tools.)

Sort of problem. I've tried Power + vol-down & Power and RE button, as per instructions to get device into fastboot mode.
[…]
Is my device in fastboot mode or some other mode?

That puts the device into Tow-Boot's USB mass storage mode. There is no fastboot mode, because Tow-Boot is not fastboot. Fastboot is the Android bootloader.

I finally managed it, just now (why I am starting this thread) I think into fastboot mode. I have a permanent BLUE led, with usb cable connected to LINUX. However I can see two (2) new devices on my Linux PC.

BOOT_MNJRO
&
ROOT_MNJRO

I have access to both of these.

What do I do, Please?

Those are the 2 partitions on your phone's eMMC. You can mount them, but if you want to install a new OS, you will want to instead flash an image onto the entire eMMC, not mount the preexisting partitions on it.

See: https://wiki.pine64.org/wiki/PinePhone_P...o_the_eMMC