Arduino as ISP/USBTinyISP used to burn ATMega1284P bootloader

Hello,
i'm trying to burn an arduino-compatible bootloader@20mhz on a fresh ATMega1284P set on a Sanguinololu board.
I started using an Arduino UNO as ISP, no way, can't get out of sync_error, but i managed to burn an attiny2313 so i built an USBTinyISP and i came back to the atmega.
Now, with the tinyISP, FUSES and LOCK bit can be succesfully written as also a simple(working) blink.hex sketch but
when i try to write the bootl using both avrdude and arduino ide i get the following error:

syskrack@pc~$ avrdude -v -patmega1284P -cusbtiny -U flash:w:ATmegaBOOT_1284P.hex
avrdude: Version 5.11.1, compiled on Oct 18 2011 at 21:17:35
[...everything ok...]
avrdude: 65700 bytes of flash written
avrdude: verifying flash memory against ATmegaBOOT_1284P.hex:
avrdude: load data flash data from input file ATmegaBOOT_1284P.hex:
avrdude: input file ATmegaBOOT_1284P.hex auto detected as Intel Hex
avrdude: input file ATmegaBOOT_1284P.hex contains 65700 bytes
avrdude: reading on-chip flash data:
Reading | ################################################## | 100% 85.08s
avrdude: verifying ...
avrdude: verification error, first mismatch at byte 0x10000
0x90 != 0xff
avrdude: verification error; content mismatch
avrdude: safemode: lfuse reads as F7
avrdude: safemode: hfuse reads as D8
avrdude: safemode: efuse reads as FD
avrdude: safemode: Fuses OK

avrdude done. Thank you.

Trying different bootloaders i have the same error in different addresses.
I didn't manage to find on google similar problems and USBTinyISP should work with every avrdude-supported chip, but i don't see other possible cause then an incompatibility(bug in the tinyisp code) issue as well.
Any idea, suggestions? tnx a lot!

CrossRoads built and has boards for sale with that chip. He could tell everything you need to know.

http://arduino.cc/forum/index.php/topic,61126.420.html