Look for the Official ROM (I don't have it) and then put it in to SDFUSE and reflash.

http://www.needrom.com/mobile/lenovo-k900-2/

Take note to read the forum properly, here they say the ROM may not work.

Need a memory card, create folder sdfuse and copy to install on this ROM (SZB tailed).
a) normal phone boot into Android OS, use a USB cable to connect PC, the pop-up screen, select USB mass storage devices, and turn on USB storage device;
b) New sdfuse folder, compiled droidboot.img, recovery.img, boot.bin, radio_firmware_6360.bin, system.img.gz copied to the phone sdfuse directory;
Note: Make sure before upgrading phone there is a certain amount of power
2. T card upgrade process
Long press VOLUP + POWER_KEY enter droidboot, a menu appears and select the fourth SDUPDATE, the bottom of the screen you can see the progress and status upgrade
See "SDCARD UPDATE SUCCESS!!!" Indicates a successful upgrade

I've seen a. original ROM for download at this thread before:
http://forum.xda-developers.com/showthread.php?t=2256075

Go search for it, that thread is very active. Nowadays you can do almost anything..no need to go to the shop to restore back..

I'm gonna play around with VIBE ROM a lil longer..but personally I prefer the one I used previously:
K900_1_S_2_019_0113_130903_DVT3_CPUsign_root.rar

Having battery issue,  each reply on lowyat forum cost me 2% battery.  . .  Is very hard to use like this

bro which version u choose ?
can share download link ? cannot tahan the battery lia ...

is that possible i freeze all china app ?
standby time is good but using time is very very bad, if i don't touch the phone when mail, chat any notis i don't care, it can last for day with data on ....
but once i start to check, u can see battery drop like no ppl business, check mail, check chat, open fb for 15-20 minute it drop 15-20% battery .... siu lia la ...

So far for me.....ok i guess i am one of the lucky ones....lets see if i hit below 20 % again.

Erm sorry the picture too big.

Can anyone tell me how long does it take to fully charge this phone? Mine is taking almost the whole nite.

Anyone know how to revert back to Lenovo stock international ROM? I am having issue with inaccurate GPS, wanna send back for warranty, need to flash back to stock rom first.

how well can the battery perform? i believe phones that use Intel CPU wont last more than 24 hours (im okay with that, i got a power bank).

maybe will get this beast on Christmas.

Selling my K900 16GB. Bought on 17/7
RM 900

Take note: Dont do this often...
Li-ion battery are not design to drained to 0%...
It might kill the battery instantly...(Some might survived it)

How long have you used the phone? How often do you charge your phone?

not sure if your battery is wearing out. just my 2 cents though.

I just try wipe cache and factory reset but no use. After reboot still show the welcome screen only.