unicorn engine exception on mapped memory

Question

I'm trying to emulate a MIPS 32 big-endian binary. Unfortunately, it throws an exception on the first instructions. I tried to start it from the second, and third instructions as well:

#!/bin/python3

from unicorn import *
from unicorn.mips_const import *

stack_size = 3 * 4096
load_address = 0x80023000
stack_base = load_address + 24*1024*1024 + 4096

def load_unicorn():
    mu = Uc(UC_ARCH_MIPS, UC_MODE_MIPS32 + UC_MODE_BIG_ENDIAN)
    er = open(r"blob", "rb")
    emulate_blob = er.read()
    mu.mem_map(load_address, 0x1000 + 24 * 1024 * 1024)
    mu.mem_map(stack_base, stack_size)
    mu.reg_write(UC_MIPS_REG_SP, stack_base + stack_size)

    mu.mem_write(load_address + 0xf00, emulate_blob)
    er.close()
    return mu

def decompress(mu):
    decompress_start = 0x800246AC
    decompress_end = 0x80024730

    buffer_address = 0x20000000
    buffer_size = 20 * 1024 * 1024 * 4 #0x2000000

    mu.mem_map(buffer_address, buffer_size)

    dest_buffer_address = buffer_address

    mu.reg_write(UC_MIPS_REG_A0, 0x8002917c)
    mu.reg_write(UC_MIPS_REG_A1, 0xD4AAEBC)
    mu.reg_write(UC_MIPS_REG_A2, dest_buffer_address)
    mu.reg_write(UC_MIPS_REG_A3, buffer_size)
    #mu.reg_write(UC_MIPS_REG_PC, decompress_start)

    mu.mem_write(stack_base, b"\x00" * stack_size)
    try:
        mu.emu_start(decompress_start, decompress_end)
    except Exception as e:
        print(e)
        print("IP: 0x{:x}".format(mu.reg_read(UC_MIPS_REG_PC)))

    total_size = mu.reg_read(UC_MIPS_REG_S5)
    decompressed_data = mu.mem_read(dest_buffer_address, total_size)
    return decompressed_data

memory_unit = load_unicorn()
data = decompress(memory_unit)

When I read the memory at decompress_start (print(mu.mem_read(decompress_start,1024))), I get the following: bytearray(b'\'\xbd\x00(\'\xbd\xff\xb8\x8f\xa3... which corresponds correctly to the instructions in this code (\x27\xbd\xff\xb8 is addiu sp, sp, -0x48)

What could be wrong here? thanks!