Default p970 won't boot and no change after flashing firmware

my friend OB stuck on LG logo when turned on,but screen goes black after 40s,strangely it does same after flashing new firmware but screen doesn't turn black. it stay on LG logo so I wait for hours,unlucky there's no change on screen.

I've tried some flash method like SFT,KDZ,offline/online update use official or patched rom from v10a,v20a,v20s,v30a,etc but still no luck..after reboot it doesn't perform any wipe or even enter recovery/cwm

on recovery mode (VolUp+G+power) there's a dead android with red triangle on it,and the recovery menu appear if home key is pressed but only vol+- that working I can't choose any options there not even perform wipe

here's the video

any help please..

thanks in advance
★ I've worn this darkened armor for so long now, there's no mote of light left in me. ★