yashsingh1/xdaforums huggingface dataset:
[MTCB Android Head Units Q&A] webdude12:
I do have my unit, it is connected. Have a bad ground loop causing feedback to Bose amp. Narrowed it down to the Illumination wire. Been troubleshooting it all day. Came in to take a break and get some food. I have some ideas on how to fix now, but when I go back out want to take my computer with and try to root this thing at the same time.

I do not miss the days of this, at least I am not upside down under the dash yet, like my car audio career days.

Some real quick notes on the unit. I will get video up soon.

1. Unit seems to be very good build quality. Back when I was in the industry stuff from China was made of what felt like beer cans. This is made of high quality metal, seems solid and good build.

2. Overall Im impressed with the install of android on this unit, but cant wait to get root and really start playing.

3. The radio app does not respond to 3rd party music apps. i.e. Google Music, Pandora, etc. It still tries to keep playing, so you end up with both the radio and the music app giving you output. Need to investigate a way to fix this.

4. Overall sound quality is very good. I competed in sound quality car stereo competitions for 6 of my 10 years in the industry, at one time had over $10,000 in car stereo equipment in a car, and while I wasnt expecting that, I think it actually sounds better then my factory radio.

Audi Specific Notes

1. The unit comes with everything you need to connect the radio up no matter what type of radio you had in the car. It works fine with my Bose system.

2. The unit fits the dash perfectly, but the black is a little glossy compared to the factory black, as of now this doesnt really bother me.

3. The unit comes with an antenna adapter for the digital antenna in the glass, and not the shark fin. So radio reception is not as good as it should be. I am going to go buy the other antenna adapter tomorrow. At one time, I know a company was making an adapter that allow you to combine both antennas, not sure if its still available. Will find out when I goto my old shop tomorrow.

Will have more soon. Let me get this ground loop fixed and get this thing rooted. Will be back :)
[MTCB Android Head Units Q&A] gangsta101:
Good one Fellas.

Just a couple of things i would really love to find out early on.

1. The quality of the built in Microphone, i saw some folks over on the AN 21 thread complaining of poor sound quality from the Mic, could you test yours with maybe a phone call or a service like skype?

2. Have you updated the build in google apps, and services yet? would love to find out if you got Google now and the GEL installed and ultimately if the OK Google hotword works well with this unit and if it could power google maps navigation
[MTCB Android Head Units Q&A] nwskipro:
awesome, glad you finally got it!

would love to hear how you resolve the issues you mention before I pull the trigger on getting one myself. so far I like this more than the windows ce unit.

when you get a chance can you take a pic that shows the glossiness of the unit relative to the rest of the center console?

also interested in how Bluetooth streaming works as well as Bluetooth calling/commands

thanks!
[MTCB Android Head Units Q&A] pakidermo5000:
Great that you got to play with your unit !

I updated the first page with your comments. Once you post the video review, I will also update it.
[MTCB Android Head Units Q&A] MMouse:
Noobie Flashing questions

I want to root my unit, but i read here that before modding i should have a proper backup.

What kind of backup do i need and what is the best way to go?

So before i root my unit i need to get a recovery mode backup of my unit?

I want to use Xpoosed framework to tune some settings.

Or do i need to get bootloader image?

Can i do one or the other out of the box?

Or do i need TWRP?

Please advise
[MTCB Android Head Units Q&A] stollerolle123:
There is nothing on the unit telling whether it a 9401 or 8401.

But on the webpage its stated as model KS9401. But of course that could be one of the difference on the two models

Just found this one which is a 8401, its only having front L/R Out

http://www.aliexpress.com/item/Free...r-PC-For-VW-Volkswagen-Golf-5/1828196306.html
[MTCB Android Head Units Q&A] dark alex:
jfyi about the Front RCA Out:

Those connectors are used on neraly every china rns.

I poinnec out wo RCA pklugs from another connector I had here and I am using this successfully with the huifei after attaching the pins to the connector.
[MTCB Android Head Units Q&A] drt1394:
Any updates here? Curious to see how well HuiFei stands behind their product. Sucks that the two people to have issues with their unit were the ones making the most progress hacking it. Hope to have you back soon.
[MTCB Android Head Units Q&A] dark alex:
What was the originating problem?

Have I overlooked something?
[MTCB Android Head Units Q&A] kwalsh24:
The clips breaking on the units that ran to the screen, which then shorted out one of the systems, the other user I think caught it in time.
[MTCB Android Head Units Q&A] 1-2-Hak:
I have been speaking with Keylo. She is sending replacement parts new main board and new cpu module. (at my freight cost) but that beats returning the unit.

I will be sending the faulty parts back so they can see what went wrong. Hopefully this will help with some Quality checks.

So hopefully the hacking will continue in a weeks time. Mind you I think I was getting close to most things working as I liked with the last Rom update. The boot time was better and I had worked out a way to be mostly happy with the brightness.
[MTCB Android Head Units Q&A] lucky-jon:
After lots of deliberation, I decided to go for one of these units - model KGAC-7648. This is a VW version, in my case for a T5 Transporter / Caravelle, but also Golf 4's and other VW's use this head unit.

I purchased from Georges / www.android-caraudio.com. He has been very helpful so far, and quick on communications. Shipping was 'from the factory' and from my order and payment took 10 days. Very efficient.

The unit came white-boxed. The included documentation is hopeless as one might expect. The head unit is also too long to slide into the 2DIN bay without some cutting. By leaving part of the plastic frame at the rear, it gave some support to the HU which might have dropped at the rear if unsupported.

I can't say I was too impressed with the quality. Nothing great. Some minor cracks in plastic parts where screws were too tight. Not serious though. The supplied cables and connectors are for standard ISO, not VW / Quadlock. Georges is sorting out an adapter for me, which I could get locally, but since you pay for it being a VW specific unit, you'd think it would connect up without buying more stuff.

I think earlier in this thread there was talk about the perm 12v and acc power wires. I have still not completed this part of the install, but I think the VW's send a CANBUS message to turn off the HU, so the acc connection is not needed - or rather needs to be connected to 12v all the time in order for the unit to power up. There is a section under SWC in Settings where it looks like you can train the HU to respond to certain commands on CANBUS.

[edit: Torque sorted..... my bad!]

Any way, over-all I am happy with the unit. Sound quality is good for a standard unit. Performance and moving around screens is smooth and fast as a stock system. The resolution issue is already apparent, although as I think was mentioned previously, it is not so much resolution as scaling. The SiriusXM app barely has enough room. Normally it shows 10 channels at a time, but being fixed in landscape mode and at such a large scale, you can see only one channel name in the scrolling list. It does still work though. From a readability point-of-view, I can't imagine fonts that really use any higher-res would be readable.
[MTCB Android Head Units Q&A] pakidermo5000:
Seem good news. I hope you can get it fixed soon. Regarding brightness. I installed an app called darker and automatized it with Tasker. It gets the sun rising and sun set times from internet and then reduces or increases the brightness (in realiity is not brightness, is opacity as it can go to 100%) gradually with time after sun rise and after sun set. It works quite well.

Now another issue. I finally managed to get my computer to detect and install the drivers when in bootloader mode. The problem is that I cannot see the device in adb. I tried everyting. rebooting the server, adding the USB VID to adb_ini, installing the drivers, ... etc. Any idea?

It is suspicious to me that in the windows device manager, I get Rockchip as "Class for Rockchip", and not under USB or ADB devices. How do you get the Huifei in your device manager ?
[MTCB Android Head Units Q&A] 1-2-Hak:
You wont see adb when it is in bootloader. Only black screen and detection as rockchip in device manager. Prety sure you wont get adb in stock recovery either and not once booted. Now you have bootloader you can safely flash twrp recovery and that will give you adb and also allow you to back up your device.

The wifi adb is the way to go once booted. I will take a look at enabling adb in the system rom once I get my unit going again.
[MTCB Android Head Units Q&A] pakidermo5000:
Ok, I need some help here to understand pretty basic things. I think I am trying to do the wrong thing. I get into bootloader mode. I get the black screen and detection of "class for rockchip" in device manager.

Now, I want to flash TWRP. My idea was to get into bootloader mode and use ADB to flash TWRP. But, I cannot connect to HuiFei when in bootloader mode because adb does not see any device.

Instead, if I boot the unit and use Wifi ADB, then I can connect to the unit.

So, should I flash TWRP through wifi ADB with the unit booted, or should I do it through bootloader mode? I could probably do it via recovery, but I do not really know how (just do update from sd card and select the TWRP I downloaded from 1-2-hak ?) otherwise, how do I do it if my adb does not detect any device?

sorry for the basic questions, but it is the first time I am doing this...
[MTCB Android Head Units Q&A] lucky-jon:
HELP Please - with VW / CANBUS / Setting SWC

OK, so now I am down to one last simple issue. How to get the ignition key to turn the unit off and on. Clearly this works because the original head unit is powered on and off by the ignition key.

My VW T5 does not have full CANBUS, but the Quadlock connector has two pins called CAN/H and CAN/L. The head unit has two wires called KEY1 and KEY2. There is no info with the unit about exactly how to program the SWC. The 'manual' p13 says "restore the steering wheel in firstly, then long press each button on the steering wheel, click related icon on the setting menu in the meantime;". Trouble is, I guess turning key on and off makes just short CANBUS message.

I can get the head unit to respond to key operation, but not correctly. My guess is that the VW sends two different codes. One 'Stereo On' when key is turned on, and a different code 'Stereo Off' when the key is removed.

What I can get is that whenever I turn the ignition ON, the HU toggles state. So it seems to link a single command to the POWER control, just like pressing the power button on the HU.

Any one any comments? Which of KEY1 and KEY2 relates to CAN/H and CAN/L, and does it matter?

Can HU on/off be controlled by two different commands, one for on, another for off? Is that how VW's work. I guess it is.

Hope you can help.

Jon.
[MTCB Android Head Units Q&A] jayroudy:
I used axxess interface for my vw to do the ignition and doors
[MTCB Android Head Units Q&A] lucky-jon:
Thanks. I'll take a look at that.
[MTCB Android Head Units Q&A] pakidermo5000:
Probably you can´t unless you find the cable in your car that sends the signal of key in. I do not know whether you have canbus decoder, but It will probably not matter. I explain.

In the quadlock there is a cable with 12V from battery (I think is grey or brown in the VW harness) with permament 12v. There is another one that only has 12v when ignition is on. This cable with electricity when ignition is on, is the one that tells the unit to power on. The unit always takes electricity from the continuous 12v, the other one is just a "switch". Then, when you turn off the unit, the electricity of this "switch" cable goes off, and the unit starts power off task. The unit remains "on " but black for a while because it must have a circuit to delay the power off. In a regular delayed swtich a condensator is charged when the unit is on, and it discharges slowly (how slow will depend on a resistor, higher resistor more slowly, and more time on " stand by")*. Once the condensator is discharged, (there is probably a comparator that compares the electricity coming from the condensator with another line coming from permanent 12v (a 555 chip does it all). Below a certain voltage, the door is shut and the unit is actually powered off.

So, your solution will be to take a cable from the fuse box, from the fuse that corresponds to key in, and use it as the switch of the unit instead of the one in the quadlock that corresponds to ignition.

The OEM radio does not work like this because it understands the canbus orders (probably thanks to the 500 eur extra). This cheap chinese stuff, does not (at least in my case).

REgarding the wrong Key1 and Key2 functions, maybe you have to change the settings on the "Factory settings" mode. There is a tab where you can select types of SWC. Password to enter Factory settings is "126"

Hope it helped.

* I say this because 1-2-Hak tried to increase the standby time of the unit via software, but it had no effect, so most probably is just a typical delayed switch.
[MTCB Android Head Units Q&A] lucky-jon:
Thanks for that. These are all useful ideas. I have a hardware electronics background. The Quadlock on my VW does carry canbus, but I have no steering wheel controls. The only control message must be on and off. There is no accessory power present on the quadlock. I would have to get that from somewhere else. I do not know if my vehicle even has any devices that are on accessory power - only the stereo.

The head unit I have (KGAC-7648) does recognize swc commands, and I can get the unit to turn on and off when the key is turned ON. But the mode of operation is wrong. It works just like pressing the power button. Key-on command turns HU on. Next Key-on turns it off. I do not understand the SWC screen in settings menu. There are two simulated LED's on each SWC button on the set up screen. They seem to light up during the programming process, but I do not know what they signify. Sometimes the whole button turns red. Looks like all the decoders are in the head unit already.... just not programmed correctly.

I will look at the factory SWC settings, but I recall a couple of posts here suggesting that changing settings there just messed up SWC completely.
[MTCB Android Head Units Q&A] lucky-jon:
More on SWC and CANBUS (for VW?)

Very strange! Went to unlock the car with remote unlocking..... and the HU switches on! Even more intriguing is that when I lock the door with remote, the Head Unit shuts down.

Tried changing SWC setting in Factory Settings. Default was set to NONE. Setting to VW/Skoda (Simple) seems to stop the SWC functions from working at all.

Set back to NONE and going back to SWC Button Programming. If I use remote door lock to program the power function, it reliably sets the head unit to turn on and off with the door lock / unlock.

:confused:
[MTCB Android Head Units Q&A] booroondook:
Does anyone know how to make the registered accounts are displayed in the settings?
[MTCB Android Head Units Q&A] getehem:
SWC

I still don't understand ...your car hasn't original SWC , right? So you don't get the two wires requested for sending signals to the main unit?
[MTCB Android Head Units Q&A] lucky-jon:
Does SWC not just use CANBUS? May be that is the confusion.

On the Quadlock connector, I have CAN/H and CAN/L from vehicle,

On head unit I have KEY1 and KEY2.

Connecting these together, the head unit can be made to respond to remote commands over that connection. The factory head unit uses serial data commands (I assume CANBUS) to turn it on and off following the ignition key. Certainly, disconnect CAN/H and CAN/L from factory head unit, and it no longer turns on / off with the ignition key.

Back to the HuiFei HU:

With CAN/H and CAN/L connected to KEY1 and KEY2, it is possible to program the head unit to respond to commands over that link. May be this is just a fluke that it works, but I believe that many vehicles now have permanent 12v to head unit only (no Acc pwr) and control the head unit using SWC (or CANBUS if they are not the same thing) even if the vehicle has no physical controls on the steering wheel.

Hope that clarifies! I appreciate you taking the time to try and get communication and terminology straight.
[MTCB Android Head Units Q&A] Gatriel:
Hey Everyone --

I have a KGL-753 which originally came with Jellybean, and I updated it to;

MCU - MTCB-KGL4-V2.02

I have Android version 4.4.2_18112014 which can be found in the repository at the beginning of this thread.

I am running Kernel 3.0.36+

I am having multiple issues that are software/firmware related, and I am hoping you guys can help me out.

First and foremost is Radio reception. It is horrible. Beyond horrible. When it locks onto a station -- there is no sound at all. Complete silence. It is as if the unit can see that a station is there, but thereafter there is no noise at all. Hopefully you can help me with this. Yes the FM antenna receives power and yes it is grounded properly. Still nothing. I have heard that the OEM FM amplifier in my car (BMW e46) doesn't play so well with this unit, so I bought a generic amplified antenna off Amazon. Its the exact same problem. I figured this unit's goal -- first and foremost should be playing the FM Radio, and being able to play it well -- it however cannot do that.

Button Layout. I think this could just be trial and error, but within the Factory Settings Menu there are a ton of "Button Output" option in the "other" tab. Can someone kindly tell me which one is the correct one for my particular unit, or in the alternative, provide me with an App that allows me to manually configure the buttons on the unit.

Thanks!
[MTCB Android Head Units Q&A] typos1:
Open it up and check the aerial is connected properly inside.
[MTCB Android Head Units Q&A] Gatriel:
I have been playing around with the Firmware, and got it to start playing the radio again, but in a metropolitan area with over 1 million people -- I can only latch onto 3 stations. :-/

Some of these station's transmission states are many kilometres away, whereas others that are just a few kms away are almost indistinguishable. Still think its the FM arial inside the unit not being connected?

Also - how can I manually program the buttons on the outside of the screen to do what they are supposed to? Currently these buttons do essentially completely random stuff. I would love it if I could program them to do what they say they do.
[MTCB Android Head Units Q&A] RyanBRZ:
Thanks and that makes sense... How would the hu know the car is in reverse without a line telling it that it is.

I looked at svxdcs site and in the 28 pin harness there is a reverse gear wire that I'm going to have to use. I just need to figure out how to let the hu know to display while in reverse. I am powering my can from behind radio using a relay... Maybe I can tap the android unit reverse line to the power line that feeds the can.. Which will get power only in reverse..

It is my understanding that the hu displays the reverse feed when this line gets 12v?
[MTCB Android Head Units Q&A] c0py:
For the button issues try flashing the correct MCU which should be "KGL1" for BMW vehicles, not "KGL4". This should map them to what they say on the physical buttons.
[MTCB Android Head Units Q&A] mikochu:
Has anyone been successful in disabling the Rearview screen when reversing? I don't have a rearview camera, so it's just a blank screen for me. I thought about freezing MRCBackview, but I'm afraid it'll mess something up or cause bootloops.

Thanks,

Mike
[MTCB Android Head Units Q&A] typos1:
I should check it out, if its connected ok then it ll be something else, several people have reported the aerials on KGLs not being properly conencted.

---------- Post added at 03:04 PM ---------- Previous post was at 03:03 PM ----------

Disconnect the wire for the rear view camera !
[MTCB Android Head Units Q&A] Karanso:
The media player always starts after into the car. He always starts from sd card on the first song again. Settings I have found none.

Rom 4.4.4
[MTCB Android Head Units Q&A] mikochu:
I have the VW CANBUS harness and the HU sticker said the reverse wire was orange. However, it also said another wire was orange. I looked at the harness and there is an orange wire and an orange/black wire from the HU to the CANBUS box. I didn't know which to cut. :eek:
[MTCB Android Head Units Q&A] typos1:
First of all dont cut it, unplug it, second, one orange is for illumination the other is for reverse in, on my Klyde they are labelled, if theyre not on yours, try them both.
[MTCB Android Head Units Q&A] peti007:
I checked the wires with multimeter. The green - green/black WIRES ARE NOT THE SAME as the blue-grey wires. I tested the canbus pins for short circuit but with not success. Sorry I have not enough knowledge for more.

I upgraded form 4.2.2 (MCU Klyde 2.02) to 4.4.4 Malaysik (MCU Klyde 2.12). The sound quality increased a lil' bit (far not perfect), 9 band EQ, the boot time is shorter (approx 25 sec), new interface not bad (the radio is very good), Android is faster, and my WiFi seems works.

The board computer still not acceptable with hold the MODE button on the SW.
[MTCB Android Head Units Q&A] parazit26:
Hi guys,

i just updated to 4.4.4 and wanted to flash another rom, but the system doesn't recognize the update.img and mcu.img. Does anyone has an advice for me maybe? SD-Card is in the GPS slot.
[MTCB Android Head Units Q&A] ultradj83:
Go to recovery by holding power and hit reset.
[MTCB Android Head Units Q&A] antfros:
Where other 4.4.4 800x480 firmware? Coduu firmware crash all time (spotify, Google,...)
[MTCB Android Head Units Q&A] kwalsh24:
But you can, as I just ordered the one mentioned, there's a YouTube clip of it it you Google the model number... well at least they are claiming its pure android.
[MTCB Android Head Units Q&A] Gatriel:
So steering wheel controls aren't working anymore. They were working earlier today.

This gets more and more frustrating. For those of you who are xda coders -- this is childs play -- but for those of us who bought a unit -- and certain things don't work, and the dev tells us to "update the software" and then the software update screws more/different stuff up. Argh.

/rant

That being said, can anyone recommend a stable/good MCU/OS combination for a KG based unit?
[MTCB Android Head Units Q&A] bobojan:
Mtcb-gs-v2.02

Hi everybody, thanks for all the post. I have a question is it possible to update my android 4.2.2 to 4.4 because as I see it is only the kgl and the others but not the MTCB-GS-V2.02

I would really be happy if someone can pm a link or write here where to download an update for it. Thanks a lot
[MTCB Android Head Units Q&A] kwalsh24:
So here's a question, now I know some don't like the 4.4 update, however I do... only thing I'm finding is that tasker isn't launching on start, has anyone managed to fix this ? Also anyone else have it where randomly the GPS monitoring mode will Ger turned off, and its volume set to -10? This has been happening to me for a while now, even in 4.2.2
[MTCB Android Head Units Q&A] typos1:
Really ? They didnt when I last looked a month ago, cool. Can you post a link ?