yashsingh1/xdaforums huggingface dataset:
[General Questions and Answers] viktorrios:
I found an explanation of one of the errors:

I: no boot messages

I: Open /cache/recovery/comand fail error= no such file or directory locale is [(null)]

stage is []

fb0 reports (possibly inaccurate)

The Unable to open DRM node: No such file or directory issue seems to indicate that there is no DRM driver running on your device (or that it failed to initialize). DRM support is a prerequisite for using this tool, as you can see. Most platforms supported by cedrus should also have DRM support, so you probably need to enable it in your kernel config and/or in the board's device-tree file.

Closing since this is not an issue of the tool but a setup issue instead.

I think I need to upload the entire message Log, maybe someone could help. So far I already know the "driver" is not booting and there is no mount of the OS. Everything else is there, and ready to receive an image. It seems the tablet was so wiped off that it doesn't even have an OS.
[General Questions and Answers] viktorrios:
There is another log report that says: error/system/framework/arm/boot.oat check fail

E:Error:/system/framework/oat/arm/wifi-service.odex has been modified md5on Thu Jan 19 01:38:12 2017

System check: FAIL!!

I: Open /cache/recovery/command fail errno = No such file or directory

local is [(null)]

cannot find/open a drm device: No such file or directory

ro.board.platform=mt8127

ro.build.id=MRA58K

....

....

ro.build.type=user

ro.build.user=builder

ro.build.product=RCT6673W23M

ro.build.flavor=RCT6673W23M-user
[General Questions and Answers] viktorrios:
This site has an RTC 668xxxx image. Will it work?

Download RCA Stock Firmware For All Models | Root My Device

Download RCA Stock Firmware and flash it in your Android device using a Flash tool to get back the native Android experience again.

rootmydevice.com
[General Questions and Answers] viktorrios:
For anyone else reading, I remember I got this RCA tablet from Amazon years ago. They were out of stock. Recently they are selling the item again: https://www.amazon.com/RCA-Keyboard-Marshmallow-Charcoal-RCT6873W42KC/dp/B01M7TSY16

And guess what?

All along the ROM version my tablet had (from the so -called-experts in Android store in my story) put the wrong ROM version.

So Amazon indicated it is: RCT6873W42KC the rom.

Googling, I found: https://naijarom.com/rca-rct6873w42m

And the site looks legit. The scatter file is there and everything matches 1 to 1 to the STOCK image.

This site also has links: https://androidmtk.com/download-rca-stock-rom-for-all-models

My question now:

Whenever I plug the USB cable in my computer, (even after installing the ADB drivers), it says that windows 10 cannot recognize the USB device.

I am ready to flash using the SP Flash tool and the ROM file, but I can't -for the love of me- make contact from the PC to the tablet.

Could anyone help me with some work around suggestions, please?

Also: Why can't I just drag-drop all scatter ROM image to the microSD and Boot from recovery using "Apply update from SDCard"?
[General Questions and Answers] viktorrios:
Ok so far everything was going full sail until I hit this brick road: Apparently I need a better USB cable. I've tried 3 different USB cables, but the device becomes unstable on win10 (switches on and off, and the "connected USB" sound dingles every 10 seconds.

Please help.

View attachment 5265921
[General Questions and Answers] Tab E:
Is the stock rom for your device?

And the reason you can't just apply update from SD card is that the scatter rom doesn't have Meta inf and updater script. So the recovery can't install that
[General Questions and Answers] viktorrios:
Yes, I checked this is the CORRECT Stock Rom for the RCA 7" Tablet Mercury Pro

I've also installed the "legacy hardware drivers":

View attachment 5265979
[General Questions and Answers] Tab E:
After you installed the drivers did you restart you Computer?
[General Questions and Answers] viktorrios:
No, I didn't restart the computer. Let me do that.

View attachment 5266017

I also tried the "newest" micro USB to USB cable I have...

I hope this works.
[General Questions and Answers] Tab E:
This is a driver problem. https://tehnotone.com/windows-10-mtk-vcom-usb-drivers-for-32-64-bit-drivers-installation-tutorial/ check this guide out. Don't use the drivers from the above site, just use the driver you instslled
[General Questions and Answers] viktorrios:
"just use the driver you installed" <- when?

I will download and install the drivers from this latest URL you've given me.
[General Questions and Answers] Tab E:
OK. You can use those
[General Questions and Answers] viktorrios:
Cool, the warnings went off, but now I need to solve the android ADB interface as well.

My RCA tablet (when off), it's not recognized as plugged device on my win10 at all, however I do get the plug-in sounds, but the device doesn't even appear on the device manager.

What else could I test?
[General Questions and Answers] Tab E:
Try checking it out from the devices and printers page. If it's showing 'unknown device' it's big trouble.
[General Questions and Answers] Tab E:
Your pc will not recognize your phone as Adb device. For that you need your phone on and USB debugging enabled. In an off state your phone will only be recognized as mediatek prelaoder.
[General Questions and Answers] viktorrios:
As soon as I plug just the USB cable, windows message appears: This USB device was not recognized by Windows previously. (etc..)

What else should I look into?
[General Questions and Answers] viktorrios:
if the tablet is on, how will the application will perform the ROM wipe? The tablet is stuck in a loop after the Dogs logo.
[General Questions and Answers] viktorrios:
gotta love windows...

It doesn't matter what USB port I plug the device on my computer (USB 2, USB 3, legacy) windows says that it doesn't recognize the tablet. The tablet is switched off. I unplug / reconnect the USB cable so that windows -at least- plays the "connected" sound, but it's futile, as the Flasher is not able to send any adb commands.

What else should I consider?
[General Questions and Answers] Tab E:
Looks like something in your phone is not working. Some part of your motherboard might have gone faulty. Happens in old devices
[General Questions and Answers] Tab E:
Keep your device plugged in and select download in sp flash tool. If your phone just gets recognised as mediatek prelaoder, the flashing might start. Try removing your battery and plugging it in
[General Questions and Answers] Tab E:
Also heard mediatek has a mode called meta mode. In this mode even though your preloader is corrupted, you can flash your rom in that mode. Try deffernt key combinations
[General Questions and Answers] viktorrios:
Ok. I will post more progress pictures later, but we agree this tablet is wreckage.

Is there a way I can upload the ROM and update it from the SD card?

The wifi and another (book?) library in the system check are preventing this tablet to startup. That's the error listing I got previously.

Also, the battery is internal.

Also, Unplugging / connecting the cable while the tablet is off, only shows the battery meter.

Should I switch it on to the boot logo loop?

Or activate recovery mode?
[General Questions and Answers] viktorrios:
I turned on the tablet, so that it will stay booting in a loop after the logo, but the result is that the tablet is still not detected by windows or the Smart Phone Flash tool. I get a warning message from the Smart Phone Flash tool about the "source power being on/off and that it can't get access to Sdram".

If I can't get the tablet to a state to be recognized by using the USB cable, what are my options?
[General Questions and Answers] Tab E:
If recovery mode is accessible just click reboot to bootloader or fastboot mode. If that's possible and device is detected by your computer in fastboot mode, your lucky
[General Questions and Answers] viktorrios:
If I push the "reset pin hole button", then I do get the Flasher to work for a brief second, and then this:
[General Questions and Answers] Tab E:
Found this somewhere

. Run Flash tools with admin as administrator

5. select the scatter file from the firmware folder you downloaded and wait for it to load. (Do not connect your phone yet and leave the battery inserted)

6. Select Download Only

7. Hit the download button

8. Now plug in the micro/type C usb end of your cable to your phone but dont plug to PC. yet

9. While hold down both volume buttons i.e up and down buttons, (Do not press the power button), Insert the Usb cable end to your PCs usb port (Please choose a port thats very reliable).

10. After a while, P Flash tool will begin to upgrade your phone,

Hold for 2mins then release them, the firmware upgrade will still continue and it will display a tick pop-up when done (this may take between 5-10mins).

LAST STEP EDITED
[General Questions and Answers] viktorrios:
Ok, this sounds plausible.

Thank you for sharing. Crossing fingers that this would work. I don't use TypeC, this tablet uses micro USB, but I get the idea. Thank you.
[General Questions and Answers] Tab E:
Sorry I didn't see the c type. I just copy pasted the guide
[General Questions and Answers] viktorrios:
Ok, at least the up+down button pressed and connecting the cable to PC after, has given a new error.

I will start with a NEW com.

The tablet itself went directly to the Recovery menu. I thought that was only possible using the POWER+"up volume". But now I see the Volumeup+volumedown buttons also take me to the recovery menu in the RCA 7" Tablet Mercury Pro.

Any other advice I should consider?
[General Questions and Answers] Tab E:
When the phone goes in the recovery mode, is there an option called reboot to fastboot or reboot to bootloader
[General Questions and Answers] viktorrios:
yes sir. There is.

I set it to bootloader.

Black screen in the tablet appears, and it reads "Bootloader mode".

I start adb: bootload devices.

Nothing is returned on the PC command prompt.

That means (somehow) the USB port of the tablet is not working with the PC.

But if I connect its USB cable to the charging outlet, it charges normally. So it is not a problem on the usb port of the tablet.

Somehow the tablet isn't recognized as a device for this reason in all of the Window's messages.

So I am really wondering what to do (it's a mix between hardware and software problem?).

I tried 3 different (high quality) USB cables to plug the tablet and that it will get recognize but windows 10, rejects ALL 3 of them WITHOUT the tablet being connected, saying: "This USB device has not been previously recognized". And it's just the USB cable connected, no tablet, nothing else connected.

So I don't know what else I should look for.

I do have soldering instruments. Fiddling with the hardware is nothing too difficult to do, but I want to extinguish all possibilities without going to that extreme.
[General Questions and Answers] Tab E:
Have you installed adb drivers? If yes go to fastboot mode and type fastboot devices not adb devices. If a certain serial number comes you can proceed
[General Questions and Answers] Tab E:
The problem is a just due to poor Chinese hardware in your tablet

EDIT : I have faced this problem from a long time with my old Micromax phones
[General Questions and Answers] viktorrios:
yes, but the fact that I can overcome this problem soldering my own components, is out of the question :)

I just need to flash this thing, but by traditional means instead of brute force.

Also, of all things considered: is there not a way to upload the rom to the SD card?

I guess not with this image rom (from what I've referred from this thread), since mounting/unmounting will not be considered "an upgrade from SD card"....

I get it that the device can't be "flashing" to a temp directory while the mount/unmount from the SD is happening....

..but... is there a possibility where I could just do it?
[General Questions and Answers] viktorrios:
Also, there is this little thread: https://forum.hovatek.com/thread-12618.html

about flashing only flashing bootloader...
[General Questions and Answers] Tab E:
The problem is you are using a stock recovery. The stock recovery can't flash system.img or other images. Making a flashable zip is out of question because a stock recovery will only accept files signed by your oem. Only ways are fastboot and sp flash tool. OR porting TWRP
[General Questions and Answers] viktorrios:
Welp, what do you know?

Does this means that in fastboot I can use the smart phone flash tool by pressing the DOWNLOAD button?

Please reply @Tab E , I will be waiting for further instructions as to what to do next.

I don't want to blow up this only chance now that the device is recognized. Please help.
[General Questions and Answers] ineedroot69:
yes try doing root integrity check it should say the partition that got corrupted
[General Questions and Answers] Tab E:
The options that I see

Try different version of sp flash tool

Install adb fastboot platform tools,

Reboot to bootloader on your phone and FOLLOW FROM HERE

unlock bootloader with fastboot oem unlock

transfer your firmware to that directory, open command window. Check all the files that end with ". Img" like system.img boot.img recovery.img

In command prompt write all these commands for all the img files

fastboot erase system

fastboot flash system system.img

Fastboot erase recovery

Fastboot flash recovery recovery.img

Fastboot erase boot

Fastboot flash boot boot.img

Fastboot erase "name of other files ending with .img

Fastboot flash xxxxx xxxxxx.img
[General Questions and Answers] Tab E:
Here are step wise instructions.

Connect your phone and type in command prompt

fastboot oem unlock
[General Questions and Answers] viktorrios:
oh shoot:
[General Questions and Answers] Tab E:
Try

fastboot flashing unlock
[General Questions and Answers] Tab E:
Oh no. Oem unlocking isn't enabled in developer options. This way looks tough
[General Questions and Answers] viktorrios:
It doesn't allow.
[General Questions and Answers] Tab E:
Try a factory reset in recovery mode and then retry fastboot oem unlock
[General Questions and Answers] viktorrios:
but the fact that the device IS recognized in fastboot correctly identified, says that the tablet (not phone, this is a tablet) is having a port conflict of some sort in the PC when it is connected.

Asides from the fact, that when I press the up + down volume, I go straight to bootloader menu.

I tried changing the USB cable, and the current one connected is the one that has gotten far to this point than the others.

So the thing as I see it:

1. We have the correct image ROM. But it's scattered and needs to be FLASHED. We know the flasher application works, since it has returned valid errors regarding the device

2. When the RCA Mercury Pro TABLET is off, I need to press the up + down buttons to "make it visible for the PC", the Windows connected USB device sound plays, but then the flasher says: I can't reach the ROM.

3. When I activate the flasher with the rom image, then I hold the up + down buttons in the TABLET and then I connect the cable to the PC: Error, messages appear as not being able to detect the Tablet. Tablet then, proceeds to switch on the RCA Dog logo and MercuryPro and stays in boot loop.

4. So far trying bootloader commands have given us more information, but the Bootloader is locked. To my understanding this can only be unlocked from the developer's menu inside the OS, which we can't access since we have the boot loop problem.

5. I can "unsolder" the battery, but that will yield no result (the battery is non-removable) since the ORIGINAL problem with this badly flashed TABLET is a file related to WIFI as I described it earlier in page 1 of this thread. Since the system check LOG can't pass that file, the system stops and we loop again from the MercuryPro logo (boot logo loop).

6. I feel that the task of fixing this RCA Mercury Pro 7" TABLET is possible, since we have discarded all hardware failures now.

What's the next step we could take?
[General Questions and Answers] viktorrios:
Ok. Let me see how that goes.

Also in the boot menu I see "Apply update from ABD" <-- maybe we can do something with this?
[General Questions and Answers] ineedroot69:
no via recovery mode there's is root integrity check it should say what missing file or corrupted partition
[General Questions and Answers] viktorrios:
Since I unplugged the cable, I can't contact the tablet anymore from the PC:
[General Questions and Answers] Tab E:
What's showing up in the devices menu
[General Questions and Answers] viktorrios:
I don't have a corrupted partition. I have 4 corrupted files and the following errors (as seen from the .log in the boot menu):

I=no boot messages

I:Open /cache/recovery/command fail errno = No such file or directory

locale is [(null)]

stage is []

reason is [(null)]

cannot find/open a drm device: No such file or directory

fb0 reports (possible inaccurate):

/// bunch of info about graphics and pixels

ro.bootloader=unknown
[General Questions and Answers] viktorrios:
I unplugged the cable carefully, waited for 3 minutes, re-insert, Windows "connected" sound fires, and it's recognized again for fastboot, after Factory reset. I tried: fastboot oem unlock - but the device says

FAILED (remote:

Unlock operation is not allowed

)

Also, let me do this: recovery mode > root integrity check so I can list the files that are corrupted. Maybe there is a way to push them to the device by unpacking them from the ROM that I currently have?
[General Questions and Answers] Tab E:
Now the only way left is SP flash tool.
[General Questions and Answers] viktorrios:
System check returns:

Error: /system/framework/oat/arm/wifi-service.odex has been modifiedon Thu Jan 19 01:39:12 2017

Error: found 4 modified files

System check FAIL!

///

When I check the log errors I find:

E: Error:/system/framework/arm/boot.oat check fail

Plus all these others:
[General Questions and Answers] viktorrios:
Kind sir, that's what we've been trying to "connect" with the RCA TABLET since page 1 of the thread.
[General Questions and Answers] ineedroot69:
look like just need to flash system.img
[General Questions and Answers] Tab E:
If nothing above works use an older sp flash tool version
[General Questions and Answers] viktorrios:
Ok, I am following.

What do I need to do?

My current Flash screen looks like this:
[General Questions and Answers] Tab E:
U

Untick everything EXCEPT system and hit download
[General Questions and Answers] viktorrios:
yes there is.
[General Questions and Answers] viktorrios:
This ROM image is different than the BADLY FLASHED ROM image by the Android cheap store I mentioned at the beginning of the thread. Files will not match. This is why I am trying to flash back the complete ORIGINAL ROM which I have now ready in SP Flash Tools from the screen captures in this thread.
[General Questions and Answers] viktorrios:
but how? Using ADB?

We've mentioned ADB can't read the device, but it DOES recognize it ONLY in fastboot mode in the PC
[General Questions and Answers] Tab E:
Try using another version of sp flash tool and flash it normally. Lest forget fastboot. You cant do anything with a locked bootloader.
[General Questions and Answers] :
You switch device from Fastboot mode to Normal mode running

adb devices
adb reboot
[General Questions and Answers] viktorrios:
oh? ok. I will try this next time. Reboot doesn't send it to the Dog logo start?
[General Questions and Answers] viktorrios:
*** THE REAL PRODUCT ****

It occurred to me that I should go back and check on Amazon if the tablet is still available (so I can read the description for RCA original Stock ROM), I know... crazy but it actually happened:

https://www.amazon.com/RCA-Keyboard-Marshmallow-Charcoal-RCT6873W42KC/dp/B01M7TSY16

And it turns out this ORIGINAL RCA TABLET's name doesn't have anything to do with Mercury PRO, but in reality, the tablet's name is

RCA Voyager Pro 7​

Looking around the forum, I found this thread:

https://xdaforums.com/t/guide-rca-voyager-rct6873w42-unlock-boot-loader-and-root.3582973/

So, not only the cheap android store flashed the wrong ROM, it also had the WRONG NAME. This explains why it took more than 4 years to find the Original Factory Rom. But at last, everything is here and ready to be flashed. I need to resolve the cable contact or some way to make this work with the unremovable battery since pushing volume up and down doesn't really work to "awake" the Tablet's identification (and connection sound) in Windows 10, pro.

What else should I try to flash this?

Thanks.
[General Questions and Answers] Tab E:
Oh. So you were flashing a worng rom. Thank God it didn't get flashed or else it would have got bricked.
[General Questions and Answers] Tab E:
Get the CORRECT Stock Rom and flash it. It should work. When you got the brom error yesterday I immediately doubted if it is the wrong rom
[General Questions and Answers] viktorrios:
Yeah, so basically I got everything sorted out, but there is no way for me to connect the TABLET to the PC to initialize the flashing.

Gosh! We're so close to complete this.

I don't know what else I need to do for the USB cable and the tablet to be picked up by Windows 10.
[General Questions and Answers] Tab E:
So in a powered off state it is not detected by your pc as mediatek vcom??
[General Questions and Answers] viktorrios:
Correct. It is not picked up in an off state. I posted pictures about it on page 1
[General Questions and Answers] Tab E:
You are good to go. Just find your stock rom and install it
[General Questions and Answers] viktorrios:
I already have the stock ROM: RCA_RCT6873W42M_MT8127_20180315_6.0

The only thing I can't is having the PC recognize the tablet with the USB cable.
[General Questions and Answers] viktorrios:
I found another USB cable (a very reliable one) and I got this message:

So what happens is that I connect the cable and it starts reading, but then it seems there is a restriction of some sort in the system (maybe antivirus/firewall?) and then the connection is lost after 10 seconds, hence the message: 2. Target might be shutdown unexpectedly or target lost power supply.

I guess the tablet does this from factory behavior to avoid being flashed?

Immediately after detecting device in com4 and losing it, the tablet reboots into Dog logo and Boot loop.
[General Questions and Answers] Tab E:
Try the fix you used yesterday. And congratulations on your senior membership
[General Questions and Answers] Tab E:
This one
[General Questions and Answers] viktorrios:
Hi. What do you mean by "senior membership" <- Cool! What's it about?
[General Questions and Answers] viktorrios:
I really wanted to thank you all for reading this thread and post all the help you've provided with your experience. I was so frustrated by all the years that have gone by and that this tablet basically just stopped working after a simple request to "flash it" to reset the forgotten password.

Today I feel really stupid. After catching a lot of rest, I decided to open Ebay to see if I could find my own tablet, and sure enough, someone posted the tablet, but I noticed he snapped a pic of the FCC ID (thanks God for law regulation!) in which I saw the number of the ROM OS tablet.

MY TABLET has this serial:

FCC ID: A2HRCT6773W22

IC: 9903A-RCT6773W22

So I guess it's back to square one, looking for this stock ROM. :(
[General Questions and Answers] viktorrios:
So the closest number I got was this ROM:

RCA_RCT6773W22BM_MT8127_20180316_6.0

So it should be: RC_RCT6673W22 xx_xxxxxx_xxxxx version I should be looking for, right?

But I cannot find any SPECIFIC rom with this description. Further, Amazon (like I mentioned in my previous post) describes this tablet with the other ROM number I mentioned.

What puzzles me the most is the fact that the tablet, gets picked up with this new RELIABLE USB cable, but drops the signal, shorts the tablet, the tablet turns itself on, proceed to Dog Logo and boot loop, and Flash tool just sends this message:
[General Questions and Answers] Tab E:
Are you on a desktop or laptop? If on a desktop, try plugging the USB cable behind the cpu