[Android General] Tzul:
I tried it with my MT6582-based phone, and the SPFT actually works with the battery removed. Meaning USB power is sufficient. But removing the battery isn't necessary, because it works just as well with it in place. Maybe it was necessary for some really old platforms, maybe not.

The PMU actually includes real current and voltage measuring hardware. Because the battery's state of charge is normally estimated with a combination of the "voltage method" and coulomb counting, which requires periodic measurements of both voltage and current.

The problem is that not all of the PMU's measurements are "published" to the SysFS on all devices. Which is why the Battery Monitor Widget app quizzes you about certain facts on the first start, as it can't detect everything automatically.

As I mentioned previously, the SysFS (/sys, not to be confused with /system) provides interfaces to certain Linux kernel internals in the form of a virtual file system. The power management stuff is under /sys/class/power_supply/. If you take a look inside /sys/class/power_supply/battery/, you'll find some (virtual) files, including one that is related to current: "BatteryAverageCurrent". As the name implies, this publishes the average battery current - but only the charging current. And since it's an average, it is updated rather sluggishly. Some other devices I've seen do publish instantaneous current info, for charging and discharging.

Anyway, the file "uevent" there is kind of a summary of all values. If you run this little shell command in a terminal, you can watch the values change in real time:

while true; do echo -----; cat /sys/class/power_supply/battery/uevent; sleep 3; done

(Cancel with Ctrl+C, or just close the terminal window)

Sounds good! I have a Chinese-made USB coupler that can measure voltage and current. I'd like to get this "deluxe" model some day, but it's almost always out of stock.

Which custom recovery exactly? If it's my TWRP, then you don't need "Beta-SuperSu-v2.49.zip", because it has the complete version of SuperSU v2.52 built-in. There should be an "Install SuperSU" button in the "Advanced" menu. Or just leave TWRP with the "Reboot" menu, and it should offer to install SuperSU.

Thanks!

Yeah, if people read my wall of text, it should be clear that the SPFT can only do its job at one specific point in time, namely near the beginning of the boot process, when the preloader is active. You can press the "Download" or "Read Back" buttons in SPFT at any time. You can even connect the USB cable at any time, e.g. while Android is still running. But the SPFT will only start working once the preloader is running. Plugging in the USB cable while the tablet is off will boot up the tablet automatically, so you don't have to do anything else. If the tablet was already running with the USB cable connected, just turn it off or reboot.

Good to see that you've figured out the "@" stuff. :good:

Well, you can't apply "incremental" updates with the SPFT, only complete and raw partition images.

SPFT update packages usually always include the preloader, after all it is marked as "download" (to be flashed) in the scatter file. But it is a common practice to exclude the preloader partition from being flashed (that's what the little checkboxes in the SPFT partition list are for).

There's no reason to be paranoid about it - I've flashed the preloader on dozens of devices already and never once had a failure. But on the other hand, when you're new to the SPFT, then it's probably not a good idea to start with flashing the preloader. Practise on some less critical partitions first, like the recovery, until you're sure that everything works.

I don't know of any reason that requires you to update the preloader. It doesn't have an effect on Android (as far as I know), so you can probably forever keep the one that was preinstalled on your device. But some people want to live on the cutting edge and install every update they can get their hands on... ;)