Need help with android on shield tablet

Xtreme Gamer · May 6, 2016

Is the dtb file from the KitKat recovery usable for marshmallow on shield tablet? Or are there different dtb files for the different android os updates? Thanks for the help guyas!!!!

laufersteppenwolf · May 27, 2016

First off, I know I'm very late to the party, but I wanna answer it in case someone else is gonna wonder about DTB files in the future, as this affects many, if not all modern android devices, but especially because this could actually hardbrick the tablet for good

Short answer: no, it is not compatible, every update needs its own DTB

Long answer:

DTB is short for "device tree blob", and as the name indicates it contains all kinds of information about the device and is run after the bootloader and before the kernel. The kernel actually relies on the DTB to "tell" it about the devices specs. This is why the source code for the DTB is actually within the kernel sources and gets compiled every time the kernel is compiled. As this already suggests, the DTB and the kernel must match in order for the device to boot up.

As I am developing a custom kernel for the shield tablet myself, I know that this is even more the case on the shield. Nvidia kinda screwed up the bootloader, making not only the kernel depend on the DTB, but also the bootloader itself. Which means that if the DTB does not match the bootloader's required DTB, you will hardbrick the tablet with not even the slightest hope of unbricking it. While you can use (slightly) modded DTBs with the according bootloader (such as the DTB I released alongside my kernel in order to accomplish overclocking of the GPU by raising the EDP limits), KitKat and M are way different, and you will almost certainly brick your device.

Xtreme Gamer · May 27, 2016

32 minutes ago, laufersteppenwolf said:

First off, I know I'm very late to the party, but I wanna answer it in case someone else is gonna wonder about DTB files in the future, as this affects many, if not all modern android devices, but especially because this could actually hardbrick the tablet for good

Short answer: no, it is not compatible, every update needs its own DTB

Long answer:

DTB is short for "device tree blob", and as the name indicates it contains all kinds of information about the device and is run after the bootloader and before the kernel. The kernel actually relies on the DTB to "tell" it about the devices specs. This is why the source code for the DTB is actually within the kernel sources and gets compiled every time the kernel is compiled. As this already suggests, the DTB and the kernel must match in order for the device to boot up.

As I am developing a custom kernel for the shield tablet myself, I know that this is even more the case on the shield. Nvidia kinda screwed up the bootloader, making not only the kernel depend on the DTB, but also the bootloader itself. Which means that if the DTB does not match the bootloader's required DTB, you will hardbrick the tablet with not even the slightest hope of unbricking it. While you can use (slightly) modded DTBs with the according bootloader (such as the DTB I released alongside my kernel in order to accomplish overclocking of the GPU by raising the EDP limits), KitKat and M are way different, and you will almost certainly brick your device.

Hey, thanks for the response! I downloaded your modded dtb and kernel files for my shield tablet, but never flashed it. But what my problem is (now knowing that each android version needs its own dtb file) that I cant find a DTB file for shield tablet wifi marshmallow I hope that either you can send me your unmodded dtb file for shield tablet marshmallow or at least point me in the direction of where to get it. Because I just cant seem to find it in the downloadable android os recovery from Nvidia. Unless I am misunderstanding you and you are actually saying that the DTB is built into marshmallow.

One other issue I was really hoping you could help me fix because it is REALLY irritating me. I have 3 custom roms 2 of which are stable but are missing one important thing that the one unstable rom has. I use Resurrection Remix newest version and Dirty Unicorns newest version and Unofficial cm13 by temasek. My annoying problem with RR and DU is that I can connect to Xfinity WiFi but never detect an internet connection. But as soon as I got to the unofficial cm13 temasek rom or back to stock rom. I can connect and detect internet connection. on RR and DU as soon as I go into a browser session while connected to xfinity wifi, the connections kicks me off. Can you somehow help me figure out what is different between cm13 temasek and the other 2 custom roms with the xfinity wifi issue? I installed the xfinity wifi app but that didn't help just incase you were gonna ask.

I know I probably should have made a new thread on this issue. But I have been looking everywhere I could and never got ANY help on this annoying issue and I am by no means a dev at all. I just thought that if a android dev actually responded to my dtb issue then maybe you could fix this side but still very irritating issue for me. Thanks if you can. I would greatly appreciate it, you have no idea.

laufersteppenwolf · May 27, 2016

41 minutes ago, Xtreme Gamer said:

Hey, thanks for the response! I downloaded your modded dtb and kernel files for my shield tablet, but never flashed it. But what my problem is (now knowing that each android version needs its own dtb file) that I cant find a DTB file for shield tablet wifi marshmallow I hope that either you can send me your unmodded dtb file for shield tablet marshmallow or at least point me in the direction of where to get it. Because I just cant seem to find it in the downloadable android os recovery from Nvidia. Unless I am misunderstanding you and you are actually saying that the DTB is built into marshmallow.

One other issue I was really hoping you could help me fix because it is REALLY irritating me. I have 3 custom roms 2 of which are stable but are missing one important thing that the one unstable rom has. I use Resurrection Remix newest version and Dirty Unicorns newest version and Unofficial cm13 by temasek. My annoying problem with RR and DU is that I can connect to Xfinity WiFi but never detect an internet connection. But as soon as I got to the unofficial cm13 temasek rom or back to stock rom. I can connect and detect internet connection. on RR and DU as soon as I go into a browser session while connected to xfinity wifi, the connections kicks me off. Can you somehow help me figure out what is different between cm13 temasek and the other 2 custom roms with the xfinity wifi issue? I installed the xfinity wifi app but that didn't help just incase you were gonna ask.

I know I probably should have made a new thread on this issue. But I have been looking everywhere I could and never got ANY help on this annoying issue and I am by no means a dev at all. I just thought that if a android dev actually responded to my dtb issue then maybe you could fix this side but still very irritating issue for me. Thanks if you can. I would greatly appreciate it, you have no idea.

Well, I think I should have an old DTB lying around somewhere, but you should flash the DTB correlating to your installed ROM (if you're running stock, otherwise the DTB shipped with the ROM/Kernel). And no, you didn't get me wrong, the DTB isn't inside Android but actually has its own partition.

Your wifi issue can actually be caused by several things, such as the wifi firmware not matching the wifi drivers within the kernel (which is most likely), a buggy kernel in general, Issues within the ROM's framework (not supporting the driver),...

What I would do in your situation is to completely reset your device by restoring a stock ROM using NVIDIA's recovery images. This also has the side effect that you would be flashing a stock DTB (at least it should, downloading an image ATM to make sure )

Then I would go on flashing one of the buggy ROMs and see if the issue still persists on a clean install. If it does, you should probably open a new thread specifically about this issue as we would then have to go into grabbing logs (both logcat and kmsg) and other deeper stuff. Feel free to ping me if you need help

EDIT:

I just checked, the recovery images do include the DTB, it's just not being flashed seperately, but within the file "blob". I simply compared the blob with my DTB as the headers must be identical of both DTBs, and it matched:

Spoiler

Xtreme Gamer · May 27, 2016

1 hour ago, laufersteppenwolf said:

Well, I think I should have an old DTB lying around somewhere, but you should flash the DTB correlating to your installed ROM (if you're running stock, otherwise the DTB shipped with the ROM/Kernel). And no, you didn't get me wrong, the DTB isn't inside Android but actually has its own partition.

Your wifi issue can actually be caused by several things, such as the wifi firmware not matching the wifi drivers within the kernel (which is most likely), a buggy kernel in general, Issues within the ROM's framework (not supporting the driver),...

What I would do in your situation is to completely reset your device by restoring a stock ROM using NVIDIA's recovery images. This also has the side effect that you would be flashing a stock DTB (at least it should, downloading an image ATM to make sure )

Then I would go on flashing one of the buggy ROMs and see if the issue still persists on a clean install. If it does, you should probably open a new thread specifically about this issue as we would then have to go into grabbing logs (both logcat and kmsg) and other deeper stuff. Feel free to ping me if you need help

Thank you for the great help so far. I should have clarified what I meant by the WiFi issue. It's not that I can't connect to any WiFi at all. I can connect to any WiFi that needs a password. I just have the problem with the xfinity WiFi hotspot. Like I said before, I can connect, its just the tablet can't detect any internet activity available on the xfinity WiFi hotspot. Xfinity WiFi hotspot works on the unstable uncm13 temasek and stock rom, but never works/connects properly on DU or RR. So there has to be something in the code between stock/uncm13 temasek and DU/RR. But since I'm not a dev, I can't find out what or how to fix this.

And for the DTB file mystery, after I flash your kernel and dtb and want to go back to stock kernel and dtb. Should I just reflash the blob file from what you just said.

Again, thanks again for the awesome help!!!!

laufersteppenwolf · May 28, 2016

15 hours ago, Xtreme Gamer said:

Thank you for the great help so far. I should have clarified what I meant by the WiFi issue. It's not that I can't connect to any WiFi at all. I can connect to any WiFi that needs a password. I just have the problem with the xfinity WiFi hotspot. Like I said before, I can connect, its just the tablet can't detect any internet activity available on the xfinity WiFi hotspot. Xfinity WiFi hotspot works on the unstable uncm13 temasek and stock rom, but never works/connects properly on DU or RR. So there has to be something in the code between stock/uncm13 temasek and DU/RR. But since I'm not a dev, I can't find out what or how to fix this.

And for the DTB file mystery, after I flash your kernel and dtb and want to go back to stock kernel and dtb. Should I just reflash the blob file from what you just said.

Again, thanks again for the awesome help!!!!

Well, as I said, it is possible that CM and Stock use a different firmware and/or driver than RR and DU. The real issue is that the actual cause can be in several parts of the system, and finding that can be a real pain in the ...

I have been working on the Galaxy Tab 3 once, trying to get wifi up, while I managed to make it search for wifi networks after days of work, I never got it to work... So I am used to finding wifi issues

What I would need you to do is to grab some logs (logcat and kmsg) when enabling wifi, connecting to the hotspot and trying to access the internet. Otherwise it's just pure guessing.

If you wanna go back, THIS is the DTB shipped with the Android 6.0.0 stock ROM. Simply flash it via fastboot and the kernel either via recovery or fastboot as well