Boot Loop

[vvildcard]

I think I did something kinda stupid on my K9C6… I was checking out the BIOS options and disabled USB and PS/2 devices during preboot (part of the BIOS Fast Boot settings). Now I’m in a boot loop and getting the “Preparing Automatic Repair”.

1. Windows 10 (Creator’s Edition) > Recovery Settings > Boot to BIOS
2. Set Fast Boot to Enabled and disabled PS/2 and USB during boot.
3. Save and restart > Windows loads fine.
4. Use the Switch to Android app to reboot.
5. Bootloop…

It appears to be booting normally once, then rebooting to attempt the “Automatic Repair”, then back to a normal attempt. During the normal attempts: the red Teclast characters show for 2-3 sec, the first Windows circle dot shows, screen flashes off and right back on to the red Teclast characters, then 3 of the Windows circle dots before a full reboot. During the “Automatic Repair” attempts, everything’s the same except that it says “Preparing Automatic Repair” instead of the Windows circle dots.

What I think is happening is a boot failure due to the USB not loading. I’m not being presented with the Multi-boot and I’m guessing it will stay that way until Android loads successfully? USB drives get power to their LED’s, but any keyboard I’ve tried doesn’t light up at all (obviously because I disabled the pre-boot USB checks).

Holding Volume Down at least pauses it at the “DNX FASTBOOT MODE..”, but my desktop doesn’t detect it (again, I’m sure it’s because I disabled the USB).

I read the stickied ‘unbrick’ post (and many more)… but everything requires hardware I don’t have (eeprom programmer) or assumes USB works. Does anyone else have a trick up  their sleeve for getting me out of this loop?

Thanks!

[vvildcard]

Update:

I let it boot loop all night to drain the battery, then cracked it open and desoldered the battery leads this evening. My hope was that would give it a full BIOS reset (a la CMOS reset), but after resoldering and recharging the battery, it’s still doing the exact same loop. Grrr!

[Oracle_ed]

On my Plus II, holding the Volume UP and Power keys takes me into the bios.

Have you tried that?

[vvildcard]

Thank you for your suggestion… unfortunately, Vol + does nothing (same as if I was not pressing it).

FWIW, Vol – brings me to DNX Fastboot Mode… Vol + and Vol – brings me to DNX Fastboot Mode with an additional note that the request was received and to let go of the keys. In both states, my desktop (Win10) does not recognize there’s even a device attached. The USB port on the tablet is only providing power, as far as I can tell.

[vvildcard]

Update:

I tried this kinda crazy (DO AT YOUR OWN RISK!) suggestion… it did not work, but also did not further damage the tablet.

Shorting BIOS chip Pin 2 to Ground while booting: http://tricks10000.blogspot.com/2015/10/how-to-reset-ufei-cmos-of-windows.html

[vvildcard]

Update: Success!

I bought an EEPROM Programmer, 1.8v Adapter and a SOIC8 Test Clip to flash the BIOS. After flashing v1.13 (w/ eMMC fix), it booted right up and everything’s just as I left it.

A few notes from my adventure:

1. You have to have the battery disconnected when trying to program the BIOS chip. I didn’t do this at first and my reads would be different every time (and looked nothing like the 1.13 BIOS). Once I un-soldered the battery (just the red wire), everything worked great. In hind sight, this was really silly of me not to do from the get-go… the battery is supplying power (presumably 1.8v) and the EEPROM Programmer is supplying power (also 1.8v)… you don’t have to do any math to figure out that’s going to be too much power. I’m just glad it wasn’t enough to fry the chip.
2. Some of the forums and YouTube videos I came across had mixed comments about having to reverse pins or do odd configurations for the Clip > 1.8v Adapter > EEPROM Programmer… but that was not the case for me. I did Pin 1 to Pin 1 all the way through my setup. On the EEPROM Programmer, it has two sections, one for 24XX and one for 25XX… just make sure you use the 25XX section.
3. The (Windows 10) driver and software I used was from this video. The video itself is not that helpful, but he has a link in the video comments to the driver and software.
4. The test clip is pretty finicky… there’s just not a lot to grab. To make sure the pins are making contact, they should be pushed back into the clip. You’ll hear if they *click* out. Just keep at it until you get a good grab, then be very careful not to bump or twist it. After looking at a lot of other chips in Google Image searches, most SOIC8’s have more to grab and the one in the X98 Pro is pretty flat.
5. I don’t know why, but the tablet does not like to turn on when the back is removed… I got it to work a few times if I used something plastic to push the power button, but it mostly wouldn’t do anything until I had the cover back on. The actual button is metal and I suspect it needs something non-conductive to activate.
6. You can save a few bucks if you buy all your parts from the same vendor on AliExpress (they’ll ship together). I got mine for less than $10, total. I don’t have the product links with me, but I’ll try to remember to post them later.

[vvildcard]

Here’s the links to the stuff I used:

https://www.aliexpress.com/item/1-8V-adapter-for-Iphone-or-motherboard-1-8V-SPI-Flash-SOP8-DIP8-W25-MX25-use/32707148719.html

https://www.aliexpress.com/item/Free-Shipping-Hot-BIOS-24-25-93-Programmer-SOIC8-SOP8-Flash-Chip-IC-Test-Clips-Socket/32360054566.html

https://www.aliexpress.com/item/CH341A-24-25-Series-EEPROM-Flash-BIOS-USB-Programmer-with-Software-Driver/32280480269.html

[dan grab]

Excellent job Congrat

 

[vvildcard]

Update: Success!!!

I ordered an EEPROM programmer, 1.8v adapter and a SOIC8 SOP8 Test Clip (links to the ones I bought… they worked for me, but there are tons available)… after a lot of messing around with them, I finally got the BIOS flashed and, as expected, it’s back online! Woohoo!

A few notes from my adventures:

1. DO NOT enable the Windows “Fast Boot” options in the BIOS (not to be confused with FASTBOOT, a tool to interact with the firmware)… it disables USB support during boot and screws everything up. You won’t be able to connect a keyboard to push F7 to interrupt the boot process, nor will you be able to boot from a USB drive, etc.
2. You must disconnect the battery (red wire) before the EEPROM Programmer will read the BIOS chip properly. Side note: I didn’t do this at first and the area around the chip started getting warm. I’m sure it was getting power from the EEPROM Programmer and the battery… When I noticed, I was surprised I didn’t burn the poor thing up (literally).
3. Keep the SOIC/SOP pins lined up as labeled (pin 1 goes to pin 1… non flipping or whatever). The 1.8v adapter goes into the 25XX side of the EEPROM Programmer (it’s labeled if you look closely). The EEPROM Programmer turned off when I flipped anything the wrong way.
4. The test clip contact teeth will slide off the contacts pretty easily. You can hear them *click* when they’re knocked off. When the clip is properly attached, all the contact teeth will be pushed back… if any teeth aren’t pushed back, they’re likely not making contact. There wasn’t much on the chip for the clip to grab so it took a few tries to get it right. Open the clip all the way, line it up with the ‘nose’ pressed firmly against the PCB, then very slowly close the clip onto the chip. If you hear the *click*, try again.
5. When ordering from AliExpress, you can save a few bucks if you buy everything from the same vendor.

[favio]

not sure if you are going to see this ever.. but worth to try

 

im having the exact same problem with a teclast X80PLUS

BUT i can log in to BIOS , i dont see white screen just goes directly to windows repair and loop like you describe

but i can access the bios with keyboard… cant fix it reparing or installing new windows or ubuntu or anything! i dont have a bios to flash 🙁

[Author]

Posts