can't stop autoboot via uart Iomega ix2-dl(ng) (1 reply)

Hello, I want to flash my ix2-dl(ng) to openwrt.
To do this, I need to stop the “autoboot” process during the boot phase.
But I can't do this because the device simply does not respond to any keystrokes (“Enter”, ‘Esc’, “Spice”, etc.).
I tried several different adapters (ch341-uart, pl2303, CP2104, cp210x) to connect with the parameters 115200 8N1 (minicom, putty). The boot log is displayed.
Only GND TX RX is connected
That is, at this point, I start pressing random keys, but to no avail. There is a countdown from 3 to 0, and then it boots up.

Retry count exceeded; starting again
Hit any key to stop autoboot:   0

Full boot log.

         __  __                      _ _
        |  \/  | __ _ _ ____   _____| | |
        | |\/| |/ _` | '__\ \ / / _ \ | |
        | |  | | (_| | |   \ V /  __/ | |
        |_|  |_|\__,_|_|    \_/ \___|_|_|
 _   _     ____              _
| | | |   | __ )  ___   ___ | |_ 
| | | |___|  _ \ / _ \ / _ \| __| 
| |_| |___| |_) | (_) | (_) | |_ 
 \___/    |____/ \___/ \___/ \__|  ** ix2-nand ** ** uboot_ver:0.0.8 **

 ** MARVELL BOARD: DB-88F6282A-BP LE 

U-Boot 1.1.4 (Oct 28 2011 - 15:19:29) Marvell version: 3.6.1 - EMC

U-Boot code: 00600000 -> 0067FFF0  BSS: -> 006CFB00

Soc: 88F6282 A1 CPU running @ 1600Mhz L2 running @ 533Mhz
SysClock = 533Mhz , TClock = 200Mhz 

DRAM (DDR3) CAS Latency = 7 tRP = 7 tRAS = 20 tRCD=7
DRAM CS[0] base 0x00000000   size 256MB 
DRAM Total size 256MB  16bit width
Addresses 8M - 0M are saved for the U-Boot usage.
Mem malloc Initialization (8M - 7M): Done
NAND:1024 MB
Found ADT7473, program PWM1 ... OK
Flash:  0 kB

CPU : Marvell Feroceon (Rev 1)
Found kernel at 0x100000
Found initrd at 0x400000

Streaming disabled 
Write allocate disabled


USB 0: host mode
PEX 0: interface detected no Link.
PEX 1: interface detected no Link.
Net:   egiga0 [PRIME]
egiga0 no link
BOOTP broadcast 1
BOOTP broadcast 2
BOOTP broadcast 3
BOOTP broadcast 4
BOOTP broadcast 5

Retry count exceeded; starting again
Hit any key to stop autoboot:   0 

NAND read: device 0 offset 0x100000, size 0x300000

Reading data from 0x3ff800 -- 100% complete. 
 3145728 bytes read: OK
## Booting image at 00800000 ...
   Image Name:   Linux-2.6.31.8
   Created:      2019-06-17  12:13:03 UTC
   Image Type:   ARM Linux Kernel Image (uncompressed)
   Data Size:    2502832 Bytes =  2.4 MB
   Load Address: 00008000
   Entry Point:  00008000
   Verifying Checksum ... OK