[Windows 8 General] _gl:
I unbricked my W3!

To recap, I changed some BIOS settings to trouble-shoot my USB 3.0 hard disk, and why I couldn't boot my USB 2.0 pen with my diagnostic tools (seems now it has to be formatted UEFI-boot compatible):

a) I turned off something USB-related (probably disabled 'XHCI handoff')

b) AND I set it to boot into the UEFI shell 1st (I didn't want to do that, but that's how it was set before I started meddling with it - not sure why it didn't cause a problem originally, probably a combination of settings).

Result: all USB ports dead, native keyboard dead (as it's apparently USB). Tablet always boots into UEFI shell, no way to stop it/exit shell/change boot device/get into BIOS settings without keyboard or bootable USB pen. So effectively bricked!

Pipo support were useless, offering me firmware (not BIOS) reflashing tools and images that need BIOS access and/or USB booting to work. They still haven't understood the problem after several emails (EDIT: and then stopped replying altogether!). But there is a way:

Warning - I really don't recommend opening the device. I cracked the digitizer despite being reasonably careful, unless you have plenty of experience, it's super easy to damage the tab. But if you're desperate or skilled:

Opened the shell (remove 4 black screws by the 3G stick section first, then prise open the usual way with soft tools, careful not to bust the case or any components near it). The clips are VERY hard to unlock, and in the process I cracked the digitizer :crying:. I haven't broken anything I've tried to fix in years, so that sucked. Correction - really sucked. Turns out that the right side of the case (with the 3G stick) is weaker structurally, so I think there was too much stress on the digitizer while trying to prise the clips open.

Download high-res pics of the insides.

The BIOS chip in mine is a flash rom, Winbond W25Q64FW, SOIC8 package. Unlike PCs there is no battery backed CMOS chip holding the BIOS settings, they're stored permanently in the flash chip, and no reset jumper that I could see. And no combination of holding hardware buttons during boot did anything - so you cannot reset the BIOS at all.

Google says 'get a BIOS programmer (or something with flashrom) & a SOIC8 clip, try programming it inline'. Nice idea - except the cheap Ebay programmers are all 3.3V, and this chip is 1.8V. Don't try it - very likely you will fry it (or the tab circuits)! Needs some kind of logic level converter, or an expensive programmer that supports 1.8V flashing. And probably waiting to get it from China or HK. Unless you're an electronics whizz or got da cash, nasty. On the plus side it would probably work - there seemed to be no chip read/write activity whilst stuck in the UEFI shell, so a BIOS dump (for later editing with various AMI APTIO tools) and/or programming a new one (or just corrupting the settings' checksum to trigger a defaults load) should be doable.

Spent several days researching this, didn't like any of the options. Then I found a mention that sometimes, grounding the chip's CLK or data IO pins during boot can trick it into thinking its settings are corrupted, and loading the defaults instead. Very risky unless you know what you're doing + high chance of BIOS corruption imo. Shorting CLK (pin 6) to GND (pin 4) at specific moments during boot didn't work (only locked up the tablet, scary).

GND to Data Out (pin 2) briefly (see pic), at the right time during boot (it seems just before the PIPO logo shows) WORKS! Bang, booted back into Windows as though nothing was wrong! But on restart got stuck in the UEFI shell again (I guess it didn't overwrite the old settings permanently, and they passed the check this time). But a 2nd Data Out grounding attempt worked again, so it wasn't a fluke! Then Windows -> System Recovery -> Advanced -> Get into UEFI BIOS -> restart got me in, USB keyboard worked, and the bad settings were already fixed - Save & Exit - Tada!

Of course now my touchscreen is partially dead due to the crack :(. Need to find a replacement digitzer now (may have found one but can't get it just yet). Or I might resell and get a new tab, maybe the recently announced Pipo Core-M with 2560x1600 screen when it arrives. I do like the Pipo design and spec choices overall, but the touchscreen issues are either shipping damage, design flaws or lousy quality control, not good (EDITl: no, that problem was a faulty/noisy charger, a universal 9V PSU mostly fixed it, see post #80).

And no way to recover BIOS settings is criminal Pipo! Something as simple as 'hold volume-down during boot to reset BIOS settings to defaults' would fix this. Most people getting caught out will need to send their device back - useless!

What have we learned?

Persistence pays off.

Don't mess with the BIOS settings unless you're 200% sure, especially nothing USB-related!! (though I'm sure there are many other ways to brick it).

And maybe make a BIOS backup right now (see my last post) ...