Firmware RBR40 2.5.1.16 keep disconnecting and auto update again after downgrade

I had a RBR40 and RBS40 which was working fine ever since I bought it last year. But since yesterday the firmware got auto upgrade to 2.5.1.16 and it had been disconnecting every few mins. I tried to use the belwo telnet trick to force it not to upgrade but it still upgrade back to 2.5.1.16 whenever it detect internet connection (I even pull out the internet line when I do the downgrade so it won't auto upgrade it when I work on the orbi satellite downgrade). I also tried to block the keyboard with fw.updates1.netgear.com, netgear.com and such but it still auto download the firmware again and installed it. I'm really appreciate if someone can help on this because I'm in the mid of Working from Home and the internet is disconnecting every few mins on my remote session and it's really frustrating and feeling helpless. Thanks

1) Launch your favorite web browser and go to <Router IP Address>/debug.htm

 2) Login <username> <password> when prompted

 3) Check Enable Telnet

 4) Start a Telnet session.  I use Putty.  Enter the <Router IP Address> Telnet is using port 23

 5) You can skip this step if you like.  I am calling it out for illustration purposes only...  

Type nvram show | grep auto_* <ENTER>

You will see a list similar to this:

root@RBR50:/# nvram show | grep auto_
vpn_access_mode=auto
wl_auto_antenna=1
set_auto_agreement=0
orbi_auto_upgrade=1
ipv6_autoConfig_dns_assign=0
ipv6_autoConfig_dns1=
ipv6_autoConfig_dns2=
upnp_enable_autoScan=0
ipv6_auto_dns_assign=0
bas_auto_conn_flag=0
orbi_auto_upg=0
autofw_port0=
ipv6_auto_dns1=
ipv6_auto_dns2=
qos_auto_bandwidth=0
green_enable_autorefresh_status=0
enable_dev_auto_refresh=1
wl_rate=auto
auto_check_for_upgrade=1
auto_update=1
root@RBR50:/# root@RBR50:/#

 The 3 configurations highlighted above you will want to update the value from =1 to =0

orbi_auto_upgrade=1

auto_check_for_upgrade=1
auto_update=1

 6) To update run the following commands:

nvram set orbi_auto_upgrade=0  <ENTER> (no spaces after set)

nvram set auto_check_for_upgrade=0 <ENTER> (no spaces after set)

nvram set auto_update=0 <ENTER> (no spaces after set)

 7) Type the following commands to confirm the 3 configurations are set to =0

nvram show | grep orbi_auto_upgrade <ENTER>

nvram show | grep auto_check_for_upgrade <ENTER>

nvram show | grep auto_update <ENTER>

 8) After you confirmed the 3 configuration values are set to =0 then type nvram commit <ENTER> (this step will save the changes)

 9) Type exit to terminate the telnet session