In the tflite quantized Mobilenet v2, from the repository, the first conv operation has a non-zero offset ... there is no activation. The offset is 128. So either provide a conv which uses signed int8 and 0 offset, or do what tflite does and handle it as quantized uint8 convolution with 128 offset value.
You can see the quantization offsets in Netron in the node properties input data  -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/dmlc/tvm/issues/2351#issuecomment-502534147
