MK808B help please - No signal / black screen

[malfrat]

Hi freaktab community and devel, (thx all droiguru for great devel)

i never get my mk808b original rk903 to work. Got the 2a power.

got an rca rled2845a hd ready tv.
Spec:
led panel
16:9
1366x768
480i,480p,720p,1080i,1080p (auto-detect scan not manually configurable)

supported hdmi port resolution:

resolution - horiz scann freq - vertical scan freq - format

720x480 - 31.47 - 59.94 - 480i
720x480 - 15.734 - 59.94 - 480p
1280x720 - 37.5 - 50 - 720p
1280x720 - 45 - 60 - 720p
1920x1080 - 31.25 - 50 - 1080i
1920x1080 - 33.75 - 60 - 1080i
1920x1080 - 27 - 24 - 1080p
1920x1080 - 56.25 - 50 - 1080p
1920x1080 - 67.50 - 60 - 1080p

i try every roms (720p and 1080p) finless (thx finless great devel),lewi (thx lewi great devel), hybrid, geekbuying, stock with no luck, i also see that the first time i flash in rktool i've got a pink square. No way to get the "Found RKAndroid Mass Storage USB" now to flash the only way is the paperclip option that give me a green one. "Found RKAndroid Loader Rock USB" of course i use the finlesstool too, both flash mk808b without errors. In device manager i see 'class for rockusb device/RK30 Device'. I try the nice nand unbrick tip from finlessbob to put in the MASK ROM mode to fix a possibly nand error, but nand is ok. I try to 'adb shell' as for my rooted smartphone with no luck, no mk808b adb device driver in device manager anyway.... i buy a 28$ 5v powered pal/ntsc switchable hdmi to av(rca) for nothing too...

There's a thing i miss ? I read and read all over different forum like a noob, some say: cheap hdmi cable,insufisent power,bad nand...the only thing i havn't read is someone that buy a tv directly from the chinese rk manufacture . it's the kernel seem pretty buggy that it make hard to the devel to get a full working one with all display.
Omagamoon (thx omegamoon great devel) seem to give a clue for the 'no signal/black screen ' issue but seem to be for mk808 only due to kernel. If i take the omegamoon mk808 kernel i'll loose BT for sure but wifi too ? And how to get back my mk808b to have a pink square in rktool (i cannot do the 'switch' )? And in finlesstool 'reboot to flash mode' give me a ' Device can not do flash mode, because it is not msc device'.

Any sugestion from the guru before i put it to garbage ?

Regards

sorry my bad english, i don't speak english everyday.

if only i bought a mk808 instead and if my lg-c800g 1ghz could only have a video output.... hé hé

[ididmytime]

Have you tried the Omegamoon kernel?

It can easily be restored to the stock mk808b kernel afterwards.

[malfrat]

Have you tried the Omegamoon kernel?

It can easily be restored to the stock mk808b kernel afterwards.

where is the stock kernel for mk808b ? in the stock update.img ?
Some say that is the hardware (hdmi cable,mk808b board power regulator) and other tell that is software,an unsolved kernel bug doesn't be fixed by rockchip (what i think,omegamoon give some clue this way as i read)

i load the omegamoon kernel with mk808b finless 1.7 , i can see for a fraction of second a bleue screen but just when i play a lot with the mini hdmi to hdmi cable supplied with my mk808b. At least there is a hint that my cable is too cheap to handle to signal...i think.

i've order on **** two kind of gold platted cable and coupler just to try out. one cable is a straight mini hdmi to hdmi gold platted cable. an other is '3FT Gold Plated HDMI M/M Cable Version 1.4 with two ferrite cores' that i'll use a mini hdmi to hdmi coupler. i'll give a try or lose an other 20 bucks

stay tune

'Rockcheap' don't want to provide mk808b kernel source apparently....

[bjbumblebee]

do you have the mk808b hooked up to the tv while you are flashing?

[neomode]

AW: MK808B help please - No signal / black screen

I think this is a Issue with the TV.
As I read your Screen Support 13xx this Resolution is not in the Kernel. You need a Kernel that's Support the Resolution of your TV. Take a look at omegamoons Kernel Build for you Device.

Neomode Freaktab.com Developer

[malfrat]

do you have the mk808b hooked up to the tv while you are flashing?

i try both way, but i should to hook up ?

thx

[malfrat]

I think this is a Issue with the TV.
As I read your Screen Support 13xx this Resolution is not in the Kernel. You need a Kernel that's Support the Resolution of your TV. Take a look at omegamoons Kernel Build for you Device.

Neomode Freaktab.com Developer

Sadly, Omegamoon seem to have no full working mk808b kernel release, only for mk808. He still work on it. he have a kernel for mk808b that fix the no signal issue but wifi/bt didn't work anymore,he try to figure out that piece of code... anyway i don't know where to get this kernel, i think he doesn't release. Did i should flash a rooted firmware and this kernel and plat around with adb ? http://www.omegamoon.com/blog/index....y130202-114743

thx

[bjbumblebee]

i try both way, but i should to hook up ?

thx

it doesnt harm it, make sure you don't have ur usb( keyboard/mouse etc.) plugged into ur mk808b or it may not boot up.
The reason i originally asked is that a faulty power supply(2a usb plug) may have been the problem and powering up via laptop usb would have determined this fault...

regards

[malfrat]

it doesnt harm it, make sure you don't have ur usb( keyboard/mouse etc.) plugged into ur mk808b or it may not boot up.
The reason i originally asked is that a faulty power supply(2a usb plug) may have been the problem and powering up via laptop usb would have determined this fault...

regards

i get back to stock china factory update_mk808b_v401j2_05_games.img and i restart to play with my supplied hdmi cable. I plug the mini plug to my mk808b slowly not completly,just to say that hdmi pins get contact with others and surprise BUT just one time i got my tv post 1024x768 60hz detect and could see a beautiful black screen with the marvelous android logo but it doesn't past this state or the hdmi pins lose contact. i'll wait a couple of day to receive my ordered new cables this week for further test. if not solved i'll try the new power supply path but i already test whit a genuine lg 5v-1a and a genuine nokia 5v-1200mha that is enough to boot without any usb device plugged in ports.

personally i'm a passionate of jtag and usbdm hobbist that playing around with many devices...
Router,cable modem and coax box is pretty easier to hack than this rockcheap until someone get the source code for rk903... long live broadcom and atheros chips. In revenge, a normal end-user like our mom doesn't have to hack the whole source code just to read email on living room tv using the mk808b wifi. A lack of supported resolution and tv brand in mk808b kernel is a shame from rockchip. On their site i cannot also see the mk808 and the mk808b,both seems to be 'generic' unbranded http://www.rockchipfirmware.com/firmware-downloads

sincerly thx to everyone to provide me help

sorry my bad english

[malfrat]

by the way i edit my first post adding this:

my rca rled2845a led tv supported hdmi port resolution:

resolution - horiz scann freq - vertical scan freq - format

720x480 - 31.47 - 59.94 - 480i
720x480 - 15.734 - 59.94 - 480p
1280x720 - 37.5 - 50 - 720p
1280x720 - 45 - 60 - 720p
1920x1080 - 31.25 - 50 - 1080i
1920x1080 - 33.75 - 60 - 1080i
1920x1080 - 27 - 24 - 1080p
1920x1080 - 56.25 - 50 - 1080p
1920x1080 - 67.50 - 60 - 1080p

[akshata]

Bad news. I also have TV with resolution 1366x768, SAdly no one is making custom kernel for this resolution.
I was able to get only picture with Omegamoon Karenl. MK808. With no sound. Usb soundcard is also not supported.
Here it is if you want to try... (No Sound Kernel MK808)

https://docs.google.com/file/d/0B6YsFi5-I2fhNEpHWG5jWERUMFk/edit?usp=sharing

[malfrat]

Bad news. I also have TV with resolution 1366x768, SAdly no one is making custom kernel for this resolution.
I was able to get only picture with Omegamoon Karenl. MK808. With no sound. Usb soundcard is also not supported.
Here it is if you want to try... (No Sound Kernel MK808)
https://docs.google.com/file/d/0B6Ys...it?usp=sharing

NOW IT WORKING GOOD AT 1080p 50hz with sound

Finally this was the poor quality supplied hdmi cable, i play aroud with it, i'm not sure if it was necessary but i also change the power supply usb cable .
-i plug the hdmi cable to the tv powered on
-i plug the mk808b to power supply and let it plugged
-after i plug and play with the hdmi cable not tight a bottom of my mk mini hdmi connector just to say that the pins connector touch themself till i could see the post on my tv and voila.

i flash finlessbob 1.7 720p on it. This way i could boot with a usb hub with 3 pendrive and my air mouse receiver connected, i use the supplied 2a power supply also. i wait for my ordered new hdmi cable, i hope with this new cable i'll be able to connect the cable normaly to my mk808b connector... really hope it help you

i will post result of my test when i receive my new hdmi cables, stay tune

sorry my bad english

[malfrat]

Bad news. I also have TV with resolution 1366x768, SAdly no one is making custom kernel for this resolution.
I was able to get only picture with Omegamoon Karenl. MK808. With no sound. Usb soundcard is also not supported.
Here it is if you want to try... (No Sound Kernel MK808)
https://docs.google.com/file/d/0B6Ys...it?usp=sharing

custom kernel have been made but there's a bug, no wifi and bt. i think they workn hard to isolate the piece of code... i hope

[malfrat]

Working great now without issue with my new hdmi-mini to hdmi cable.

Finally that cheapest but better than the supplied hdmi cable resolve my issues and for a couple of bucks.
For about 3$ on **** you can't go wrong. But also have at least a power supply 5v 2A or 3a with good usb cable to supply the mk corectly is also recommended.


resolved