The VTA bitstream generated by Vivaodo 2020.2 for PYNQZ2 doesn't work

Environment: PYNQz2, vivado 2020.2, TVM v0.8

The tutorial deploy classification works well with the official VTA bitstream. When I use the bitstream generated following Bitstream Generation with Xilinx Toolchains, the program will stop at with no log information at both host and pynq side. I didn’t change the settings in vta_config.json except "TARGET" : "pynq". I try to show the instruction stream, and the length of the instruction stream of the official VTA bitstream is 224, while the number is 331 of the bitstream generated by vivado 2020.2. After generating the instructions, there are no other reactions of the program using my bitstream.

So the questions are:

  1. where should i check to see why the program stops after changing nothing but the bitstream?
  2. why the length of instruction stream are so different using the bitstream generated with same settings?

Thank you.