[ROM][5.1.1] AOSP-5.1.1 / CM-12.1 for Lenovo a2109 (20160901)

[XotusBlack]

Hi Guys

first, big thx to all who made the AOSP rom possible - you saved a tablet !

I had every rom that is available for the A2109A - the AOSP Variant is with looooong distance the best i ever had - so smooth, no lags, not sudden shutdowns and no more battery leak if wifi is disabled - great work.
as mentioned with SU 2.65 u can get root - fantastic.
this is quite the best rom for the tablet!

 

[PJBrs]

New lollipop build, with security fixes from android for may 2016, as well as some kernel security fixes.

cm-12.1-20160512-UNOFFICIAL-kai.zip (md5: bf11c386deb0dd481c6f1caafa6d4377)

Will add AOSP later. Unfortunately, I had to apply all the May security patches by hand to the AOSP tree, which took quite some time. Happy flashing!

 

[XotusBlack]

THX, cant wait 4 it ...

btw. can anybody give me the exact A/C Output Data that fits the battery, since i got my a2109, iam missing a A/C Adapter, now after Years i can USE this tablet, so i need a faster loading

 

[jeremy6652]

The original one outputs 2000mAh which is quite a lot, a faster one might not be that healthy for the battery!

 

[XotusBlack]

u r right, but i dont want to increase the loading speed beyond manufacturer limits...thx for the 2000mAh, thats my problem, most smartphones have 1000mAh ...

 

[yaka]

New lollipop build, with security fixes from android for may 2016, as well as some kernel security fixes.

cm-12.1-20160512-UNOFFICIAL-kai.zip (md5: bf11c386deb0dd481c6f1caafa6d4377)

Will add AOSP later. Unfortunately, I had to apply all the May security patches by hand to the AOSP tree, which took quite some time. Happy flashing!

Flashed it, so far everything works smoothly. I changed from KitKat directly without any problem. Thank you again, PJBrs!

 

[red_dragon721]

I installed aosp last night and its working great. Very smooth, zero lags. I have obtained root via su2.65. I did have to reinstall cwm. The only issue I've come across is no screen recording apps works. Should I download cm12.1 instead?

 

[PJBrs]

I installed aosp last night and its working great. Very smooth, zero lags. I have obtained root via su2.65. I did have to reinstall cwm. The only issue I've come across is no screen recording apps works. Should I download cm12.1 instead?

I should think we need newer proprietary blobs for screen recording. You could try the 20160424 build, that's the last one with the new blobs. I would be very curious whether that would work...

 

[red_dragon721]

I should think we need newer proprietary blobs for screen recording. You could try the 20160424 build, that's the last one with the new blobs. I would be very curious whether that would work...

I'm currently testing build 20160424 for screen recording and it works great! I installed the Greenify app and its amazing for the lag issues on this build. Excellent work!

 

[PJBrs]

I'm currently testing build 20160424 for screen recording and it works great! I installed the Greenify app and its amazing for the lag issues on this build. Excellent work!

Hmmm.... Please note that it does contain various security issues...

More importantly though - what happens when you start a screen recording and then switch on the camera? Also, what screen recording app are you using? And thanks for testing!

Incidentally, the reason I switched back to the old blobs is that they fix video conferencing, which seems a more important use case for a tablet than making a screen recording. Unfortunately, we do not seem to be able to get both at the same time...

 

[stueymc]

I want to give the Lollipop ROM a go, and am just getting set up. At the start of this thread it mentions TWRP and CWM recoveries. Which one is better, or recommended? Also I have CWM v6.0.5.1 flashed and working. At the start of this thread CWM v6.5.0.1 is listed - is this a typo, because the link opens CWM v6.0.2.8.
Also coming from JB4.1 I suppose a full wipe is recommended?
Thanks

 

[red_dragon721]

I should think we need newer proprietary blobs for screen recording. You could try the 20160424 build, that's the last one with the new blobs. I would be very curious whether that would work...

Hmmm.... Please note that it does contain various security issues...

More importantly though - what happens when you start a screen recording and then switch on the camera? Also, what screen recording app are you using? And thanks for testing!

Incidentally, the reason I switched back to the old blobs is that they fix video conferencing, which seems a more important use case for a tablet than making a screen recording. Unfortunately, we do not seem to be able to get both at the same time...

I totally understand needing the video conferencing to work. I just finished up recording some Beach Buggy Blitz while having the front camera overlay activated and it turned out really good. Nothing lagged and there was no force closing. After that I created a video while the Cyanogenmod camera app was running in the background before I started the recording. I did that with and without the front camera overlay and had the same results. I'm using ADV Screen Recorder by ByteRev.

 

[PJBrs]

I want to give the Lollipop ROM a go, and am just getting set up. At the start of this thread it mentions TWRP and CWM recoveries. Which one is better, or recommended? Also I have CWM v6.0.5.1 flashed and working. At the start of this thread CWM v6.5.0.1 is listed - is this a typo, because the link opens CWM v6.0.2.8.
Also coming from JB4.1 I suppose a full wipe is recommended?
Thanks

Hi, first, the 6.5.0.1 should definitely be 6.0.5.1. I'm surprised though that it opens an old version. You definitely need the newer one. How did you check? Because I just downloaded it myself, and the filename at least suggests that I have the right version.

Which is better... Well, I like TWRP. It did reboot once or twice while I tried to make a backup, but nothing bad really, and it looks way nicer than cwm.

I would recommend a full wipe, yes.

 

[stueymc]

Hi, first, the 6.5.0.1 should definitely be 6.0.5.1. I'm surprised though that it opens an old version. You definitely need the newer one. How did you check? Because I just downloaded it myself, and the filename at least suggests that I have the right version.

Which is better... Well, I like TWRP. It did reboot once or twice while I tried to make a backup, but nothing bad really, and it looks way nicer than cwm.

I would recommend a full wipe, yes.

I had tried the CM11 ROM a while back, but decided to go back to 4.1. For the CM11 Rom, the recovery listed is CWM 6.0.5.1. I still had that version flashed on my tablet. The 2 version numbers looked like a typo was possible. So if in doubt, ask.
Actually I've just rechecked, and the link at the start of this thread for the mis-named 6.5.0.1 does go to a download link for 6.0.5.1, BUT it does not work in IE for me. In Chrome it works fine.....

Anyway did full wipe, installed the latest build of CM12, flashed pico OpenGapps and Superuser. Installed Google Now launcher. Could not get Now laucher to work until a Shutdown/restart. Everything working now. Will play it a bit, and then maybe try the AOSP version.

Question now, and showing my ignorance, but what is the big difference between AOSP and CM? Are there advantages to using one over the other?

Thanks for the reply, and loving the new ROM...

 

[PJBrs]

So I took a better look at the May Android security bulletin, and I noticed some security issues in the Nexus 9 video driver. This is a newer tegra device than ours. Turns out, these appear to be kernel issues (i.e., I noticed some kernel changes in the Nexus 9 kernel that are very suspicious), and some of them appear to apply to our device as well.

One patch in particular, media: tegra: nvavp: Fix arbitrary kernel write (3b407548660440c8787d94b8f71b171b277c3b8a) took quite some effort (at least, for me - remember, I can hardly programme, I'm just puzzling), but I think I managed to backport it. If you're reading this and have some programming skills, then please check whether my backport makes any sense to you. Anyway, this is what's delaying my next build, I'm testing the new kernel with the patches added right now, and all seems well.

Question now, and showing my ignorance, but what is the big difference between AOSP and CM? Are there advantages to using one over the other?

The big difference is that AOSP (Android Open Source Project) is the unpatched Android source tree straight from Google. I like to think of it as Android the way it's meant to be, with the least added frills and therefore the best performance. Problem is - this tree does not contain any compatibility patches for non-Nexus devices. (Most, if not all Android devices come with some proprietary blobs that need to be updated with every new Android version, while our blobs have not been updated since JellyBean-4.1.1, hence the need to apply a series of compatibility patches that make our old blobs work with newer Android versions.)

Custom ROMs like Cyanogen, Omnirom, Slimrom, AOKP, etc., all generally do two things. First of all, they add many compatibility patches for devices that do not have recent blobs. Especially ROMs that support tegra3 devices (P880, tf700, tf300, HTC one-X, ...) usually have already added these patches, so no additional maintenance work for me. Second, they add many features that developers like, like the privacy framework in Cyanogen, that aren't part of "vanilla" Android.

I always wanted to have AOSP, but it's hard to hunt down the right compatibility patches. That's why it's taking so long.