Amigos yo tengo un problema similar con un k750 el telefono solo es reconocido en modo com, y cuando intento flashear el main se queda en trying launch embedder bootloader, y de ahi no pasa que puede hacer? este es el log:
v0.914041/UNI
CARD SERIAL: 000
Loaded 51 flash descriptors
Open COM port OK
ChipID:8040,EMP protocol:0301

Open COM port OK
ChipID:8040,EMP protocol:0301

PHONE IS RED RETAIL PRODUCT
FLASH CID detected:49
Speed:460800
Flash ID check:890D
Flash props sent ok
OTP LOCKED:1 CID:49 PAF:1 IMEI:352557xxx CERT:RED
FLASH CID:49 COLOR:RED

Model:K750i
Brand:Generic
MAPP CXC article: R1CA021 prgCXC125954_CHINA_CL
MAPP CXC version: R1CA021
Language Package:APAC_1
CDA article: CDA102337/101
CDA version: R5A
Default article: cxc125953
Default version: R1CA021
PROVIDER: 000-00
SIMLOCKS NOT DETECTED

USERCODE:0000

RESTORATION FILE NOT PRESENT
"R1CA021_CXC125954_CHINA_CL"
YOU MUST PERFORM FULL FLASHING
WHEN "ALTERNATIVE SECURITY BYPASS" ENABLED

Elapsed: 5 secs.
Open COM port OK
ChipID:8040,EMP protocol:0301

PHONE IS RED RETAIL PRODUCT
FLASH CID detected:49
Speed:460800
OTP LOCKED:1 CID:49 PAF:1 IMEI:35255xxxx CERT:RED

REMOVE BATTERY FROM PHONE, THEN INSERT IT BACK
THEN PRESS "READY"

Open COM port OK

Trying to launch embedded bootloader...
embedded bootloader not responds !
PROCEDURE WAS STOPPED BY USER
Elapsed: 63 secs.