old_contents: import esp
  
  class FlashBdev:
  
      SEC_SIZE = 4096
      START_SEC = 0x89000 // SEC_SIZE
      NUM_BLK = 0x73
  
      def __init__(self, blocks=NUM_BLK):
          self.blocks = blocks
  
      def readblocks(self, n, buf):
          print("readblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
          esp.flash_read((n + self.START_SEC) * self.SEC_SIZE, buf)
  
      def writeblocks(self, n, buf):
          print("writeblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
          assert len(buf) <= self.SEC_SIZE, len(buf)
          esp.flash_erase(n + self.START_SEC)
          esp.flash_write((n + self.START_SEC) * self.SEC_SIZE, buf)
  
      def ioctl(self, op, arg):
          print("ioctl(%d, %r)" % (op, arg))
          if op == 4:  # BP_IOCTL_SEC_COUNT
              return self.blocks
          if op == 5:  # BP_IOCTL_SEC_SIZE
              return self.SEC_SIZE
  
  if esp.flash_size() < 1024*1024:
      bdev = None
  else:
      bdev = FlashBdev()
  
new_contents: import esp
  
  class FlashBdev:
  
      SEC_SIZE = 4096
      START_SEC = 0x89000 // SEC_SIZE
      NUM_BLK = 0x73
  
      def __init__(self, blocks=NUM_BLK):
          self.blocks = blocks
  
      def readblocks(self, n, buf):
          #print("readblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
          esp.flash_read((n + self.START_SEC) * self.SEC_SIZE, buf)
  
      def writeblocks(self, n, buf):
          #print("writeblocks(%s, %x(%d))" % (n, id(buf), len(buf)))
          #assert len(buf) <= self.SEC_SIZE, len(buf)
          esp.flash_erase(n + self.START_SEC)
          esp.flash_write((n + self.START_SEC) * self.SEC_SIZE, buf)
  
      def ioctl(self, op, arg):
          #print("ioctl(%d, %r)" % (op, arg))
          if op == 4:  # BP_IOCTL_SEC_COUNT
              return self.blocks
          if op == 5:  # BP_IOCTL_SEC_SIZE
              return self.SEC_SIZE
  
  if esp.flash_size() < 1024*1024:
      bdev = None
  else:
      bdev = FlashBdev()
  
subject: Disable debug output/checks.