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Nexus 7 2012 Version - Kernel for OTG-Charging on Android 5.0+ Coming
This one is for everyone with the in-car installs that're using a USB integration such as autodroid or the ancient version of USB-ROM.
A developer over on XDA, Sgt. Meow, is getting ready to release a kernel that supports fast-charging in host mode coming up this wednesday. Here is the thread:
It means that you'll be able to use a Lollipop versioned ROM available on XDA or elsewhere with his kernel and get the USB integration that autodroid and USB-ROM offered.
I've been testing it out for the past few days and it's working MUCH better than autodroid did and has so far been very stable. I'm using it along with Bliss Pop which is available here:
Bliss Pop is android v5.1.1 Lollipop. Here are some of the features I'm currently enjoying with it:
- USB Host-mode fast-charging
- USB Audio routed out through my DAC
- Bliss Pop automatically mounts my flash storage that is plugged into my USB hub
- 96khz 24-bit audio, DVD quality, with PowerAmp
- I'm automating the sleep options are automated utilizing tasker, with very few and very simple tasks being performed
- Keeping the screen on while charging is an option found in the Developer options now inside of Bliss Pop so that doesn't have to be automated with tasker any longer
If you're unfamiliar with the process to load one of these ROMs and are interested in upgrading later it's pretty simple.
From recovery you would..
- Wipe dalvik
- Wipe Cache
- Perform a factory data reset
- Flash your Lollipop ROM
- Flash the kernel from SGT meow after flashing your ROM
- Flash a GAPPs package compatible with your ROM
- Reboot
Just wanted to put it out there, it's worth upgrading if you're still running the 2012 version of the Nexus 7 and have been using either USB-ROM or Autodroid. You should also be able to run just about any Lollipop ROM of your choosing as well as long as you flash his kernel after flashing the ROM. I can vouch for it working with Bliss Pop though, which I like as it's a Cyanogen-Mod based ROM with some extra features added in. I'll get a video of it up later this week.
This is amazing if it really works. Thank you very much. I'm tired of leaving and checking up on the powerbank battery in the center console to charge the Nexus7 2012 tablet. How fast is the fast charge process? Can you give us a percentage per min. or 10 min. ? It drains about 5% per day in the deepest sleep with best powersaving options.
mine still drains like you mentioned, Lollipop is better with the power management I know Google integrated a bunch of extra power management into Lollipop
I think I lost about 5-8% last night while I was sleeping, but it charged back up today.
My fast charge works well, my charger that I'm using is able to deliver 2.4A of current to my tablet though and my cable I custom made to have 20AWG wires instead of the tiny 26AWG that most usb cables have so I wouldn't have as much power loss in my cable.
I can say I haven't had to unplug/re-plug the cable with the kernel in FI mode, it fast charges when plugged in.
I know previously with kitkat sometimes it would charge at the USB rate and other times at the AC rate and if it was charging USB you had to unplug/replug it to get it to the AC (fast-charging rate). I haven't had that issue.
This is amazing if it really works. Thank you very much. I'm tired of leaving and checking up on the powerbank battery in the center console to charge the Nexus7 2012 tablet. How fast is the fast charge process? Can you give us a percentage per min. or 10 min. ? It drains about 5% per day in the deepest sleep with best powersaving options.
Something else may not have considered before..
Tablet does not operate very well with a hot battery. I've been using GSam to monitor battery temperatures and voltages. Running Autodroid or in general if the battery temp approaches 156F or so, sometimes it can reach 160F from being left in the car the tablet will often lock up and force a reboot or you may have to hold down the power button until it reboots.
With the newer updates from Lollipop from google with a battery temperature over 120F the tablet WILL NOT fast-charge. It will charge, but it just maintains the battery percentage really, if it were running a lot of apps it would drain. I've noticed this several times now. It's much more stable at the higher temps on the newer kernel, I had one reboot and my battery was at 156F.
I just bought a sunshade to try to put the inside car temp in check and prevent this from happening. Battery temps above 120F aren't typically considered safe for Li-Poly batts anyhow, but I found an article showing some lithium batteries don't vent until in the 500Fs. Nevertheless when they do vent they can explode violently into flames, that can't be put out with water (water on it may cause an explosion) and requires a Class D fire extinguisher to put out. It's a metal fire.
I need to do this but have no idea how to. Every time i install something the tablet gets stuck and i have to factory reset
If I remember well you're trying to install cm-10.1-20130817-USBROM-tilapia.zip which is Timurs-tilapia ROM on a N7 2012 tablet. That ROM needs gapps-jb-20130812-signed.zip flashed along with it in order to boot.
If you're installing Autodroid-tilapia-4.4.4.build.1.2.zip you'll need Slim_normal_gapps.4.4.4.build.8.x-385.zip along with it.
You don't reboot until you flashed the google apps to go with your ROM. Also try CWM or ROM Manager from google store, it's free and it makes this whole process a whole lot easier for your project.
You could have multiple ROMs backed up and recover onto the one you choose.
But I like my powerdown video! haha. Thanks for the update. I haven't decided if i'll update yet, got a good working setup right now. Mainly worried about losing the auto backup cam.
First of all upgrade BlissPop from 07/08 ver to 07/15 ver. They fixed the wallpaper issue where wallpaper would not update when set except after reboot.
Power Management is super on BlissPop. I plugged my regular Nexus charger and it charged from 72% to full in like half an hour. Well maybe cause I didn't install Xposed Framework and others but I can tell the tablet draws less battery power than Autodroid. I've installed the new kernel too, the "no-graphite" one but I can't find any fixed install options in its setup. How does it turn off by itself when you switch off the key in ignition. Also the kernel reports my tablet as "grouper" when I installed the "tilapia" ver. See pictures.
In his bliss pop thread he has the files mixed up, check the name of the zip file if you click the link for the grouper version you get tilapia and vice versa, verify it on your hard drive I noticed the same thing when I first downloaded the grouper version and went to flash it somehow I had the tilapia version of it and then I noticed the dev has the links mixed up in his thread for bliss pop.
The FI mode options are in a directory for the system, they're located in:
/sys/kernel/usbhost/
There are 4 files in there
-- usbhost_fastcharge_in_host_mode
-- usbhost_fixed_install_mode
And two others that the kernel uses automatically when it detects it's plugged into an OTG cable.
If the USB host fastcharge in host mode one is set to 1 then fastcharging is enabled, if it's 0 then it's disabled. The same thing with the other file a 1 enables it and a 0 disables it. You can open and check them from something like root browser and just open them as a text file. You'll also be able to change them from there and save it as long as you have root enabled and you grant permission to root browser or whatever file manager app you like to use.
I mentioned to the dev while I was testing that most would not know where these files are located or how to tinker with them and he put a script into the init.d to enable the options on boot which is as follows:
#!/system/bin/sh
#This is the USB bits init.d config file.
#Delete if you don't want to use it.
He may also have hard-coded them to be '1' all of the time unless you change it, but I think he did it with a script my tablet still has his testing version of the kernel loaded on it.
As far as power management I was just using tasker to automate everything, very few profiles really I have one for when power is detected and one for when it is removed.
For Power on I have:
- Set display timeout to 24 hours
- Set Airplane mode to Off
- Set location mode to device only
- Wake screen
For power off I have:
- Set display timeout to 10 seconds
- Set airplane mode to on
- Set location mode to off
That works for me, then I have my lockscreen set to come on after 5 seconds from after the screen timing out and in the developer options I have the screen set to stay on at all times while charging.
I'm altering the display timeout in order to prevent the screen from going dim and I'm using autobrightness (my light sensor isn't blocked though). With the screen timeout always set to 10 or 15 seconds the developer option will keep the screen on while it's charging. However after the 10 or 15 seconds the screen will dim significantly, to prevent this I change the screen timeout using tasker so it stays at whatever autobrightness level it is set to.
My tablet is down right now until I get another USB micro plug for my ribbon cable, I have one in-route now though. I have the ribbon cable routed out and the usb micro plug for the N7 got damaged, I just had to replace the ribbon cable itself as well.
Also remember it doesn't fast-charge if the batt temp goes above 120F, google worked in some thermal management to the kernel. So when it gets hot it'll have to cool down before it fast-charges. It does charge though, but very slowly really just enough to keep the battery from draining a lot.
The dev mentioned possibly altering it so it will charge at a higher temp, but I'm not sure if he did anything with it yet. I think it fast-charging around 130F-135F would be more ideal, if the temp gets up to 156F it can take a while to cool down. I bought a sun-shade to try to keep the tablet's temp down but my micro usb connector went out the day before the sun-shade came in lol.. Also keep in mind you may experience reboots of the tablet or have it lock-up on you if the temp approaches 156-160F it becomes unstable at that temperature.
You can use GSam battery monitor to monitor the battery temperature, it has a widget you can add to a screen and see what the battery temp is among other information it displays. I've been using it to track down apps that cause a lot of battery drain as it logs what app is using how much power that way I can develop more tasks to kill those apps that are battery hogs while the tablet is sleeping. Everything seemed pretty good to me on blisspop though.
hi, i just singed up to reply to this thread. spent all day installing latest blisspop on my grouper, but loading oxydo revamped on top of that makes it stuck at the boot animation for hours. boots and works just fine with the blisspop stock kernel though. is it just the otg charging that i will be missing without this rom? not that i can live without it, got a dac, dvb-t adapter and a flash drive
i've tried numerous combinations of factory wipe and system partition wipe with files being flashed together or separately at no avail. only got to try the kernel #3 without graphite though. TIA!
07-12-2015, 04:49 PM
