Unable to boot into single-user mode on EX2200

I have bought two second hand EX2200 units, one was factory reset the other does not seem so.

The instructions at the below URL state to boot into single-user mode and perform the recovery from there. The problem is that the switch does not pause for a few seconds for me to press the space bar key to get to the prompt to enter boot -s command.

https://www.juniper.net/documentation/en_US/junos/topics/task/configuration/authentication-root-password-recovering-qfx-series.html

This is what I am seeing at start up. The moment I see Hit [Enter] to boot immediately, or space bar for command prompt, it shows a countdown from 1 but it goes away faster than a second and no matter how fast I press on my space bar I cannot get it to stop and give me a prompt to enter single-user mode.

U-Boot 1.1.6 (Jul 26 2011 - 03:19:50)

Board: EX2200-24T-4G 4.18
EPLD:  Version 04.100311 (0x10)
DRAM:  Initializing (512MB)
Flash: 8 MB

Firmware Version:01.00.00
USB:   scanning bus for devices... 3 USB Device(s) found
       scanning bus for storage devices... 1 Storage Device(s) found

ELF file is 32 bit
Consoles: U-Boot console

FreeBSD/arm U-Boot loader, Revision 1.1
(builder@dagmath.juniper.net, Tue Jul 26 01:25:53 UTC 2011)
Memory: 512MB
bootsequencing is enabled
bootsuccess is set
new boot device = disk0s1:
Loading /boot/defaults/loader.conf
/kernel data=0x889590+0xdd8ac syms=[0x4+0xf0f80+0x4+0xc89d0]


Hit [Enter] to boot immediately, or space bar for command prompt.
Booting [/kernel]...
Kernel entry at 0x1400100 ...
GDB: debug ports: uart
GDB: current port: uart
KDB: debugger backends: ddb gdb
KDB: current backend: ddb
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JUNOS 12.3R12.4 #0: 2016-01-20 04:27:03 UTC