ISS only supports big endian, so a MicroBlaze with an AXI bus system needs to be configured as big-endian.
This can be achieved by adding the following parameter to the MHS file:
PARAMETER C_ENDIANNESS = 0
Note: If you use a PLB bus system, the default setting is big-endian.
In SDK, check the linker script to make sure that all of the section are set to LMB.
Then use the XMD command "connect mb sim" to start the GDB server, and set the "remote Debug" to use the same port number.
In this case, it is 1234.
The program will stop at the breakpoint.