Hello Oma,

bad news: With the updated model fix from post 15, things are even worse: Neither WLAN nor Bluetooth now works, and we have a lot of error messages about OutOfMemory and OpenGL renderer in the catlog.

For WLAN, the issue seems to be:

02-13 19:14:28.740 E/wpa_supplicant(1815): wlan0: Unsupported driver 'wext'

for Bluetooth, Idn't even find any error messages, but it's simply not working...

Please find both catlog and dmesg output with this setup attached.

As I will only have time to look into this again after the weekend, please take your time - no need to hurry. And in case it looks like there is no easy remedy, I think we'll simply stay with the stock 4.1.1 ROM for this device...

Thanks again & best regards,

awl

Hello again,

final update from me before the weekend...

I have finally managed to create dmesg and catlog output after trying to activate Bluetooth: see attachments.

This has been quite difficult, as typically, just a few seconds after trying to unsuccessfully activate Bluetooth for the first time, the kernel crashes: The tablet becomes hung/unresponsive, and I get kicked out of "adb shell" with this message:

error: protocol fault (no status)

Also, I noticed that with the original stock Android 4.1.1, the WLAN driver (compiled statically into the kernel) states in dmesg log:

MT5931 SDIO WiFi driver (Powered by Rockchip,Ver 2.07) init.

while with your CM 10.1 (but the exact same 3.0.8+ kernel), the WLAN driver states on init (from mt5931.ko):

MT5931 SDIO WiFi driver (Powered by Rockchip,Ver 1.08) init.

Many thanks again in advance & have a nice weekend,

awl

Bad news: There are even two issues that need to be resolved with the most recent model fix from post #22:

(1) Even though the MT5931 driver must be included statically in the kernel:

CONFIG_MT5931=y

in the kernel config, and I do not have any mt5931.ko on Trekstor's Android 4.1.1 stock ROM, with the most recent model fix on CM10.1, I still cannot activate WLAN either.

(2) Also, Bluetooth still cannot be activated. I think that the model fix still contains a wrong Bluetooth driver. While you seem to have included Bluetooth drivers for MT6622 (system\etc\firmware\MTK_MT6622_E2_Patch.nb0 and libbluetooth_mtk.so), the Ventos tablet has BCM4329 as its Bluetooth chip:

CONFIG_BT_HCIBCM4325=y

in the kernel config file and the dmesg file for the Trekstor 4.1.1 stock ROM says:

[BT_RFKILL]: bcm4329 module has been initialized,rc=0x0

This also means that the stock kernel should already include the Bluetooth driver (as well as the WLAN driver). Still, CM10.1 does not seem to detect both drivers...!?

Do you have any idea why neither WLAN nor Bluetooth do work with the CM10.1 ROM even though the kernel should include the drivers?

In the meantime, I try to set up a 3.0.8 kernel compile environment for the source provided by Trekstor and will try to compile both WLAN and Bluetooth as kernel modules. I'll report back on my success...

Many thanks one more time!
awl

And bad luck one more time...

Now CWM recovery is back in my recovery partition, but the tablet is only recognized by Windows as "mass storage", such that I am both unable to connect with adb any more, and also still unable to boot into a proper kernel (even though I thought that I had written the original working kernel back).

Is there any chance that I can use a CWM updater script to update the kernel partition?

Currently trying to do something like this:

but it looks like this does not work for whatever reason.

What is the correct "partition" name to be used as the second parameter to write_raw_image()?

Thanks again!

OK, so finally, I'm back on track without opening the tablet:

What was needed was to clean up, deinstall and reinstall the Windows adb drivers in order to deal with the perturbing number of different device IDs that stock ROM, stock recovery, CWM recovery, CWM ROM and bootloader are using: a nightmare! The Windows tool "USBDeview" was a tremendous help with this - otherwise I would have failed...

But with the correct driver, I was able to connect again with adb while CWM recovery was running, and switch the device back to bootloader mode using "adb reboot recovery" in oder to flash again...

So I have now tried once again to install the kernel that I had successfully compiled before, and this time, I succeeded. I still don't know what went wrong when I tried this for the very first time, but now it worked anyway.

In the meantime, I have found out that indeed from booting with the stock 4.1.1 ROM and examining locgcat output that indeed, my Bluetooth chip is MT6622 and not BCM432x, even though there also is a log entry stating that the tablet also seemingly successfully activates BCM4329, but it doesn't really do this...

I am now all set for further experiments with CM10.1: Even though I am now able to manually successfully insmod mt5931.ko (in my newly compiled 2.07 version) as well as the old wlan.ko from the stock ROM successfully on top, I have not yet managed to activate WLAN again using this configuration. Maybe I need to rebuild wlan.ko myself as well...!?

And you are indeed correct in terms of the vendors providing corrupt kernel sources, or - as in my case - kernel sources that only compile without changes on a particular gcc 4.3 version, but fail with any later gcc...

Let's see whether I will be able to sort something out - I will try to do so for some more hours until I either succeed or consider this an interesting, but frustrating and futile experience. I will keep this thread updated...

Thanks anyway for your help & best regards,

awl