lg p769 flash error

p769 error while u boot erasing and flashing
any soolution


here is log

Welcome to Octoplus/Octopus Box LG Software version 2.9.1
--------------------------------------------------------------------------------
Checking data...OK
Platform: LG Infineon
Connection mode: OMAP
Selected model: P769
Please, disconnect cable, reconnect battery, connect P999 cable (with
910k resistor)
Connecting...OK
Sending preloader...OK
Sending loader...OK
Opening "LGP769_V20H.oct"...OK
Initializing device...OK
Writing Firmware...
Connecting to application CPU...OK
Erasing gpt1...OK
Writing gpt1...OK
Erasing u-boot...
u-boot not erased. Trying to skip.
Writing u-boot...Failed!
Performed by 2.9.1 Software version.