Build Environment:

• OS: Linux Mint 21.3 Cinamon(*) ... on Hyper-V of Windows

(* : Because, it was difficult to set up a build environment for "uiflow-micropython" on Windows.)

Cause:
The PSARM enable setting in the following file, which sets the build settings, was missing.

uiflow_micropython/m5stack/boards/sdkconfig.spiram_oct

Solution:
Modify the missing description as shown below, then build the firmware and write it to AtomS3R.

Before:

# MicroPython on ESP32-S2 and ESP32-PAD1_subscript_3, ESP IDF configuration with SPIRAM support in Octal mode
CONFIG_SPIRAM_MODE_QUAD=
CONFIG_SPIRAM_MODE_OCT=y

After:

# MicroPython on ESP32-S2 and ESP32-PAD1_subscript_3, ESP IDF configuration with SPIRAM support in Octal mode
CONFIG_SPIRAM_MODE_QUAD=
CONFIG_SPIRAM_MODE_OCT=y

# MicroPython on ESP32, ESP IDF configuration with SPIRAM support

CONFIG_SPIRAM=y
CONFIG_SPIRAM_CACHE_WORKAROUND=y
CONFIG_SPIRAM_IGNORE_NOTFOUND=y
CONFIG_SPIRAM_USE_MALLOC=y

# This is the threshold for preferring small allocations from internal memory
# first, before failing over to PSRAM.
CONFIG_SPIRAM_MALLOC_ALWAYSINTERNAL=8192

# SPIRAM increases the size of the firmware and overflows iram0_0_seg, due
# to PSRAM bug workarounds.  Apply some options to reduce the firmware size.
CONFIG_COMPILER_OPTIMIZATION_SIZE=y
CONFIG_COMPILER_OPTIMIZATION_CHECKS_SILENT=y
# CONFIG_RINGBUF_PLACE_FUNCTIONS_INTO_FLASH=y # Workaround required: see main_esp32/linker.lf
CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH=y
CONFIG_FREERTOS_PLACE_SNAPSHOT_FUNS_INTO_FLASH=y

Result:
8MB of memory space is now available as shown below.

Souce Code Of "Rseult":

import os, sys, io
import M5
from M5 import *
import gc

a = None

def setup():
  global a

  M5.begin()
  print("--start--")
  print("Mem-Free: " + str(gc.mem_free()))
  print("Mem-Alloced: " + str(gc.mem_alloc()))
  a = bytearray(1*1024*1024)
  print("Memory allocated : about 1MB")
  print("Mem-Free: " + str(gc.mem_free()))
  print("Mem-Alloced: " + str(gc.mem_alloc()))


def loop():
  global a
  M5.update()


if __name__ == '__main__':
  try:
    setup()
    while True:
      loop()
  except (Exception, KeyboardInterrupt) as e:
    try:
      from utility import print_error_msg
      print_error_msg(e)
    except ImportError:
      print("please update to latest firmware")

==================================================
kuriko さんありがとうございます。

AtomS3RのPSRAMがUIFlow2.0で使用できない問題が解決しました。

原因：
ビルド設定を行う下記のファイルのPSARM有効化の設定が不足していました。
uiflow_micropython/m5stack/boards/sdkconfig.spiram_oct

対策：
不足ている記載を上記英文「After:」のように修正ししてからファームウェアをビルドしAtomS3Rに書き込みます。

結果：
下記の様に8MBのメモリ空間が使用可能になりました。

(日本の方にも情報共有できるよう、日本語併記としました。)

import os, sys, io
import M5
from M5 import *

long_text = None

def setup():
  global long_text
  M5.begin()
  long_text = bytearray(1*1024*1024)

def loop():
  global long_text
  M5.update()


if __name__ == '__main__':
  try:
    setup()
    while True:
      loop()
  except (Exception, KeyboardInterrupt) as e:
    try:
      from utility import print_error_msg
      print_error_msg(e)
    except ImportError:
      print("please update to latest firmware")

But I want to reserve as heap memory.
Because I want to allocate memory as a buffer to be used for HTTP communication by "request2".

However this problem would be solved if there was a way to allocate the memory allocated by bytearray to the "request2" buffer.