I am still intrigued by the oddities around usbasp support for atmega256O. I believe I've found some interesting results. I will report them back shortly.
I bought such an 'LC Technology' programmer too and agree it is a fine board.
... no problem with t13, m2560,
Mine certainly showed problems with the m2560 related to flash>128KB, I will detail them later.
Mine came with a firmware that is a mod of Fischl 1.2. The flash is not locked so I could read it in and compare it with Fischl 1.2, so I know it is a mod, not identical. I backed it up so I can restore it if needed. Note 1.2 is old, it dates from 2007.
What is in yours? You can look at the USB manufacturer string and bcdDevice version: mine are "www.fischl.de" and "1.2" respectively. For Fischl firmware, the bcdDevice version corresponds to the firmware version.
like before some problems did crop up after reflashed with fischle firmware
That is weird. If the programmer uses the same pinout as the original Fischl usbasp, why would the Fischl firmware not work?
Mine runs (almost) fine with Fischl 1.4, better than with the original fw. Even Fischl 1.4 has problems with flash > 128KB, but I found a fix for that.
But maybe you tried other things. Can you describe what kind of problems you observed?