Crystal Chip: Black Screen after Bootup

Hi. I bought a premodded V12 with a diode fix and a cooler fix for preventing an overheating ic) and flashed it with the new 0.07 firmware (hacked) and installed the bootmanager. after putting in an old copied disc the bootmanager froze up and i resetted the console, but i only got a black screen. i could only press reset several times to load up the original sony boot screen and reflash the firmware, after doing that i could enter the bootmanager again on booting. i then tried a new cdr backup and it booted.
so i turned off the console (power supply) and when i turned on the console again after an hour it went black again. had to reflash the firmware again and it was good again. i thought maybe it flashes only into a ram memory so i decided to leave the console on standby. but just now i startet the console again and surprise surprise it enters into a black screen. i have no idea what could cause this kind of behavior.
hope you can help me.
bye, crash

I would try new firmware or reburn it at the slowest speed.

i have the newest firmware (0.07). and i burnt it at the lowest possible speed (4x). i dont get it. if it says that the flashing is done, then i assume that it is done and everything is copied correctly and the crc check is positive. and why does it work when i reflash it and reset the console, but when i turn the console off for some time it goes to a black screen again? it's freaking me out!

You're right about the CRC check. Is it possible there is a loose connection inside from shipping causing this? Does the date/time get lost as well, or..? That's about all the dumb things I can rule out.

Perhaps the problem is with the bootmanager. When this happens have you tried both memory card in,out?

yes. i tried with and without memory card
i kind of figured out that it has to be a loose connection due to the shipping, cause i was so angry that i punched the top of my pstwo and now it works everytime. problem is i dont know for how long, but i'll leave the console like that in that position and hope that the cables inside wont start to move.
bye and thx for the help
crash