I reset the silly thing and setup samba with username & password  ...the way I normally would run it.

# # # #

mrjcd@Deb:~$ telnet 192.168.1.1
Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.

DD-WRT v3.0-r41986 std (c) 2020 NewMedia-NET GmbH
Release: 01/14/20
Board: Linksys EA8500

DD-WRT login: root
Password: 
==========================================================
 
     ___  ___     _      _____  ______       ____  ___ 
    / _ \/ _ \___| | /| / / _ \/_  __/ _  __|_  / / _ \
   / // / // /___/ |/ |/ / , _/ / /   | |/ //_ <_/ // /
  /____/____/    |__/|__/_/|_| /_/    |___/____(_)___/ 
                                                     
                       DD-WRT v3.0
                   http://www.dd-wrt.com
 
==========================================================


BusyBox v1.31.1 (2020-01-14 01:15:07 +03) built-in shell (ash)

root@DD-WRT:~# ps
  PID USER       VSZ STAT COMMAND
    1 root      1028 S    /sbin/init
    2 root         0 SW   [kthreadd]
    3 root         0 SW   [ksoftirqd/0]
    4 root         0 SW   [kworker/0:0]
    5 root         0 SW<  [kworker/0:0H]
    6 root         0 SW   [kworker/u4:0]
    7 root         0 SW   [rcu_sched]
    8 root         0 SW   [rcu_bh]
    9 root         0 SW   [migration/0]
   10 root         0 SW<  [lru-add-drain]
   11 root         0 SW   [cpuhp/0]
   12 root         0 SW   [cpuhp/1]
   13 root         0 SW   [migration/1]
   14 root         0 SW   [ksoftirqd/1]
   15 root         0 SW   [kworker/1:0]
   16 root         0 SW<  [kworker/1:0H]
   17 root         0 SW   [oom_reaper]
   18 root         0 SW<  [writeback]
   19 root         0 SW   [kcompactd0]
   20 root         0 SW<  [crypto]
   21 root         0 SW<  [bioset]
   22 root         0 SW<  [kblockd]
   23 root         0 SW<  [watchdogd]
   25 root         0 SW   [kworker/0:1]
   42 root         0 SW   [kswapd0]
   43 root         0 SW<  [vmstat]
   69 root         0 SW<  [cryptodev_queue]
   70 root         0 SW   [kworker/u4:1]
   72 root         0 SW<  [bioset]
   73 root         0 SW<  [bioset]
   74 root         0 SW<  [bioset]
   75 root         0 SW<  [bioset]
   76 root         0 SW<  [bioset]
   77 root         0 SW<  [bioset]
   78 root         0 SW   [kworker/1:1]
   79 root         0 SW<  [bioset]
   80 root         0 SW<  [bioset]
   81 root         0 SW<  [bioset]
   82 root         0 SW<  [bioset]
   83 root         0 SW<  [bioset]
   84 root         0 SW<  [bioset]
   85 root         0 SW<  [bioset]
   86 root         0 SW<  [bioset]
   87 root         0 SW<  [bioset]
   88 root         0 SW<  [bioset]
   89 root         0 SW<  [bioset]
   90 root         0 SW<  [bioset]
   91 root         0 SW<  [bioset]
   96 root         0 SW<  [kworker/0:1H]
   97 root         0 SW<  [kworker/1:1H]
  734 root       728 S    /sbin/hotplug2 --set-rules-file /etc/hotplug2.rules --persistent
  738 root       776 S    /sbin/mstpd
  746 root      1756 S    watchdog
  748 root         0 SW   [kworker/1:2]
  749 root         0 SW   [kworker/0:2]
  776 root         0 SW<  [cfg80211]
  783 root         0 SW<  [ath10k_wq]
  784 root         0 SW<  [ath10k_aux_wq]
  785 root         0 SW   [kworker/u4:2]
  787 root         0 SW<  [ath10k_wq]
  788 root         0 SW<  [ath10k_aux_wq]
  907 root         0 SW<  [ata_sff]
  912 root         0 SW   [scsi_eh_0]
  913 root         0 SW<  [scsi_tmf_0]
  915 root         0 SW   [scsi_eh_1]
  916 root         0 SW<  [scsi_tmf_1]
  917 root         0 SW   [usb-storage]
  944 root         0 SW<  [bioset]
  983 root         0 SW   [jbd2/sda-8]
  984 root         0 SW<  [ext4-rsv-conver]
 1060 root      4092 S    hostapd -B -P /var/run/ath0_hostapd.pid /tmp/ath0_hostap.conf
 1085 root      4072 S    hostapd -B -P /var/run/ath1_hostapd.pid /tmp/ath1_hostap.conf
 1161 root      1332 R    telnetd
 1231 root       828 S    usmbd -c /tmp/smb.conf -u /tmp/smb.db
 1232 root       856 S    usmbd -c /tmp/smb.conf -u /tmp/smb.db
 1234 root         0 SW   [ksmbd-ath1]
 1235 root         0 SW   [ksmbd-ath0]
 1236 root         0 SW   [ksmbd-br0]
 1237 root         0 SW   [ksmbd-vlan2]
 1238 root         0 SW   [ksmbd-vlan1]
 1239 root         0 SW   [ksmbd-teql0]
 1240 root         0 SW   [ksmbd-eth1]
 1241 root         0 SW   [ksmbd-eth0]
 1242 root         0 SW   [ksmbd-lo]
 1280 root      1756 S    ttraff
 1293 root      1428 S    resetbutton
 1295 root      2616 S    startservice_f modules_wait
 1365 root      4792 S    httpd -n -p 80
 1514 root      1324 S    udhcpc -i vlan2 -p /var/run/udhcpc.pid -s /tmp/udhcpc -O routes -O msstaticroutes -O staticroutes
 1611 root       704 S    cron
 1617 root      1732 S    dnsmasq -u root -g root --conf-file=/tmp/dnsmasq.conf
 1622 root      1716 S    wland
 1623 root      1756 S    process_monitor
 1721 root      1324 S    -sh
 1753 root      1324 R    ps
root@DD-WRT:~# cat /tmp/smb.conf
[global]
log level = 1
netbios name = DD-WRT
server string = 
syslog = 10
encrypt passwords = true
preferred master = yes
use sendfile = yes
aio read size = 2048
aio write size = 2048
large readwrite = yes
security = user
mangled names = no
max stat cache size = 64
workgroup = 
bind interfaces only = yes
guest account = nobody
map to guest = Bad User
smb passwd file = /var/samba/smbpasswd
private dir = /var/samba
passdb backend = smbpasswd
log file = /var/smbd.log
max log size = 1000
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=262144 SO_RCVBUF=262144
read raw = yes
write raw = yes
oplocks = yes
max xmit = 65536
dead time = 15
getwd cache = yes
lpq cache time = 30
min protocol = SMB2
max protocol = SMB2
printing = none
load printers = No
usershare allow guests = Yes
[damnu]
comment = damnu
path = /mnt/sda/
read only = no
guest ok = no
valid users = mrjcd
force user = root

# # # #
smb passwd file = /var/samba/smbpasswd  --- that's bullshit cause it is an empty file :'(
# # # #

root@DD-WRT:~# cat /var/samba/smbpasswd
root@DD-WRT:~# cd  /var/samba/
root@DD-WRT:/tmp/var/samba# ls
smbpasswd
root@DD-WRT:~# cd /mnt/sda/
root@DD-WRT:/tmp/mnt/sda# ls
Debian-Live     Lead-Copper     lost+found      lunbuntu_16.04  old-notes       tmp-junk
root@DD-WRT:/tmp/mnt/sda# cd
root@DD-WRT:~# 

 # # # # #
  even though the stupid webif says samba is stopped I can still mount it on my Debian desktop at smb://192.168.1.1/
# # # #

# # # #

# # # #
  but ONLY if samba is set to 'public' --- NO username or password ...like so --
# # # #

# # # #

root@DD-WRT:~# ubootenv set boot_part 1 && reboot
a_pEnv->crc = d52feed7
crc32 = d52feed7
root@DD-WRT:~# Connection closed by foreign host.
mrjcd@Deb:~$ 

 # # # # #

mrjcd@Deb:~$ telnet 192.168.1.1
Trying 192.168.1.1...
Connected to 192.168.1.1.
Escape character is '^]'.

DD-WRT v3.0-r41892 std (c) 2020 NewMedia-NET GmbH
Release: 01/05/20
Board: Linksys EA8500

DD-WRT login: root
Password: 
==========================================================
 
     ___  ___     _      _____  ______       ____  ___ 
    / _ \/ _ \___| | /| / / _ \/_  __/ _  __|_  / / _ \
   / // / // /___/ |/ |/ / , _/ / /   | |/ //_ <_/ // /
  /____/____/    |__/|__/_/|_| /_/    |___/____(_)___/ 
                                                     
                       DD-WRT v3.0
                   http://www.dd-wrt.com
 
==========================================================


BusyBox v1.31.1 (2020-01-05 00:57:52 +03) built-in shell (ash)

root@DD-WRT:~# ps
  PID USER       VSZ STAT COMMAND
    1 root      1032 S    /sbin/init
    2 root         0 SW   [kthreadd]
    3 root         0 SW   [ksoftirqd/0]
    4 root         0 SW   [kworker/0:0]
    5 root         0 SW<  [kworker/0:0H]
    6 root         0 SW   [kworker/u4:0]
    7 root         0 SW   [rcu_sched]
    8 root         0 SW   [rcu_bh]
    9 root         0 SW   [migration/0]
   10 root         0 SW<  [lru-add-drain]
   11 root         0 SW   [cpuhp/0]
   12 root         0 SW   [cpuhp/1]
   13 root         0 SW   [migration/1]
   14 root         0 SW   [ksoftirqd/1]
   15 root         0 SW   [kworker/1:0]
   16 root         0 SW<  [kworker/1:0H]
   17 root         0 SW   [oom_reaper]
   18 root         0 SW<  [writeback]
   19 root         0 SW   [kcompactd0]
   20 root         0 SW<  [crypto]
   21 root         0 SW<  [bioset]
   22 root         0 SW<  [kblockd]
   23 root         0 SW<  [watchdogd]
   25 root         0 SW   [kworker/0:1]
   42 root         0 SW   [kswapd0]
   43 root         0 SW<  [vmstat]
   69 root         0 SW<  [cryptodev_queue]
   70 root         0 SW   [kworker/u4:1]
   72 root         0 SW<  [bioset]
   73 root         0 SW<  [bioset]
   74 root         0 SW<  [bioset]
   75 root         0 SW<  [bioset]
   76 root         0 SW<  [bioset]
   77 root         0 SW   [kworker/1:1]
   78 root         0 SW<  [bioset]
   79 root         0 SW<  [bioset]
   80 root         0 SW<  [bioset]
   81 root         0 SW<  [bioset]
   82 root         0 SW<  [bioset]
   83 root         0 SW<  [bioset]
   84 root         0 SW<  [bioset]
   85 root         0 SW<  [bioset]
   86 root         0 SW<  [bioset]
   87 root         0 SW<  [bioset]
   88 root         0 SW<  [bioset]
   89 root         0 SW<  [bioset]
   90 root         0 SW<  [bioset]
   91 root         0 SW<  [bioset]
   96 root         0 SW<  [kworker/0:1H]
   97 root         0 SW<  [kworker/1:1H]
  734 root       728 S    /sbin/hotplug2 --set-rules-file /etc/hotplug2.rules --persistent
  738 root       776 S    /sbin/mstpd
  746 root      1756 S    watchdog
  748 root         0 SW   [kworker/0:2]
  774 root         0 SW<  [cfg80211]
  782 root         0 SW<  [ath10k_wq]
  783 root         0 SW<  [ath10k_aux_wq]
  784 root         0 SW   [kworker/u4:2]
  786 root         0 SW<  [ath10k_wq]
  787 root         0 SW<  [ath10k_aux_wq]
  801 root         0 SW   [kworker/1:2]
  907 root         0 SW<  [ata_sff]
  912 root         0 SW   [scsi_eh_0]
  913 root         0 SW<  [scsi_tmf_0]
  915 root         0 SW   [scsi_eh_1]
  917 root         0 SW<  [scsi_tmf_1]
  918 root         0 SW   [usb-storage]
  944 root         0 SW<  [bioset]
  983 root         0 SW   [jbd2/sda-8]
  984 root         0 SW<  [ext4-rsv-conver]
 1060 root      4092 S    hostapd -B -P /var/run/ath0_hostapd.pid /tmp/ath0_hostap.conf
 1085 root      4092 S    hostapd -B -P /var/run/ath1_hostapd.pid /tmp/ath1_hostap.conf
 1164 root      1332 S    telnetd
 1206 root      2204 S    /usr/sbin/smbd -D --configfile=/tmp/smb.conf
 1214 root      1988 S    /usr/sbin/nmbd -D --configfile=/tmp/smb.conf
 1258 root      1756 S    ttraff
 1271 root      1428 S    resetbutton
 1343 root      4796 S    httpd -n -p 80
 1444 root       704 S    cron
 1508 root      1324 S    udhcpc -i vlan2 -p /var/run/udhcpc.pid -s /tmp/udhcpc -O routes -O msstaticroutes -O staticroutes
 1538 root      1732 S    dnsmasq -u root -g root --conf-file=/tmp/dnsmasq.conf
 1543 root      1716 S    wland
 1544 root      1756 S    process_monitor
 1685 root      1324 S    -sh
 1691 root      1324 R    ps
root@DD-WRT:~# cat /tmp/smb.conf
[global]
log level = 1
netbios name = DD-WRT
server string = 
syslog = 10
encrypt passwords = true
preferred master = yes
use sendfile = yes
aio read size = 2048
aio write size = 2048
large readwrite = yes
security = user
mangled names = no
max stat cache size = 64
workgroup = 
bind interfaces only = Yes
guest account = nobody
map to guest = Bad User
smb passwd file = /var/samba/smbpasswd
private dir = /var/samba
passdb backend = smbpasswd
log file = /var/smbd.log
max log size = 1000
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=262144 SO_RCVBUF=262144
read raw = yes
write raw = yes
oplocks = yes
max xmit = 65536
dead time = 15
getwd cache = yes
lpq cache time = 30
min protocol = SMB2
max protocol = SMB2
printing = none
load printers = No
usershare allow guests = Yes
[damnu]
comment = "damnu"
path = "/mnt/sda/"
read only = No
guest ok = No
valid users = mrjcd
force user = root
root@DD-WRT:~# cat /var/samba/smbpasswd
mrjcd:1000:E9A4C36F64B540B8CED9DC2BA0FB7983:162E829BE112225FEDF856E38E1C65FE:[UX         ]:LCT-00000001:
root@DD-WRT:~# 

  # # # #

r41892 works just like it should

and yea the stupid r41986 works good on WNDR3700v4 & the 160NL :')

  # # # #

mrjcd@Deb:~$ ssh root@citadel-switch.mrjcd.com
DD-WRT v3.0-r41986 std (c) 2020 NewMedia-NET GmbH
Release: 01/14/20
Board: Netgear WNDR3700 V4
==========================================================
 
     ___  ___     _      _____  ______       ____  ___ 
    / _ \/ _ \___| | /| / / _ \/_  __/ _  __|_  / / _ \
   / // / // /___/ |/ |/ / , _/ / /   | |/ //_ <_/ // /
  /____/____/    |__/|__/_/|_| /_/    |___/____(_)___/ 
                                                     
                       DD-WRT v3.0
                   http://www.dd-wrt.com
 
==========================================================


BusyBox v1.31.1 (2020-01-14 04:11:58 +04) built-in shell (ash)

root@Citadel-Switch:~# ps
  PID USER       VSZ STAT COMMAND
    1 root      1184 S    /sbin/init
    2 root         0 SW   [kthreadd]
    3 root         0 SW   [ksoftirqd/0]
    5 root         0 SW<  [kworker/0:0H]
    6 root         0 SW   [kworker/u2:0]
    7 root         0 SW<  [khelper]
    8 root         0 SW<  [netns]
    9 root         0 SW<  [writeback]
   73 root         0 SW<  [crypto]
   75 root         0 SW<  [bioset]
   77 root         0 SW<  [kblockd]
   79 root         0 SW   [kswapd0]
   80 root         0 SW   [kworker/0:1]
  112 root         0 SW   [fsnotify_mark]
  255 root         0 SW<  [deferwq]
  257 root         0 SW   [kworker/u2:2]
  469 root       940 S    /sbin/hotplug2 --set-rules-file /etc/hotplug2.rules --persistent
  498 root      1880 S    watchdog
  556 root         0 SW<  [cfg80211]
  610 root         0 SW   [kworker/0:2]
  637 root         0 SW   [scsi_eh_0]
  638 root         0 SW<  [scsi_tmf_0]
  639 root         0 SW   [usb-storage]
  674 root         0 SW<  [kworker/0:1H]
  797 root         0 SW   [jbd2/sda1-8]
  798 root         0 SW<  [ext4-rsv-conver]
  918 root      1396 S    syslogd -Z -L
  920 root      1396 S    klogd
  938 root      1232 S    dropbear -b /tmp/loginprompt -r /tmp/root/.ssh/ssh_host_rsa_key -p 22 -s
  965 root      2604 S    /usr/sbin/smbd -D --configfile=/tmp/smb.conf
  967 root      2384 S    /usr/sbin/nmbd -D --configfile=/tmp/smb.conf
 1035 root      1836 S    wland
 1047 root      3176 S    /tmp/openvpnserver --config /tmp/openvpn/openvpn.conf --route-up /tmp/openvpn/route-up.sh --route-pre-
 1186 root      4604 S    httpd -n -p 80
 1188 root       912 S    cron
 1190 root      1564 S    resetbutton
 1203 root      1880 S    process_monitor
 1388 root      1300 S    dropbear -b /tmp/loginprompt -r /tmp/root/.ssh/ssh_host_rsa_key -p 22 -s
 1389 root      1396 S    -sh
 1391 root      1396 R    ps
root@Citadel-Switch:~# cat /tmp/smb.conf
[global]
log level = 1
netbios name = Citadel-Switch
server string = 
syslog = 10
encrypt passwords = true
preferred master = yes
use sendfile = yes
aio read size = 2048
aio write size = 2048
large readwrite = yes
security = user
mangled names = no
max stat cache size = 64
workgroup = 
bind interfaces only = yes
guest account = nobody
map to guest = Bad User
smb passwd file = /var/samba/smbpasswd
private dir = /var/samba
passdb backend = smbpasswd
log file = /var/smbd.log
max log size = 1000
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=262144 SO_RCVBUF=262144
read raw = yes
write raw = yes
oplocks = yes
max xmit = 65536
dead time = 15
getwd cache = yes
lpq cache time = 30
min protocol = SMB2
max protocol = SMB2
printing = none
load printers = No
usershare allow guests = Yes
[SWITCH]
comment = "SWITCH"
path = "/mnt/sda1/"
read only = no
guest ok = no
valid users = mrjcd
force user = root
root@Citadel-Switch:~# cat /var/samba/smbpasswd
mrjcd:1000:FB234959C0FD6533543B250A1F7B6542:0234139080B72E1F056B6BF6D01F1AFA:[UX         ]:LCT-00000001:
root@Citadel-Switch:~# exit
Connection to citadel-switch.mrjcd.com closed.
mrjcd@Deb:~$ ssh root@160nl-switch.mrjcd.com
DD-WRT v3.0-r41986 std (c) 2020 NewMedia-NET GmbH
Release: 01/14/20
Board: Linksys WRT160NL
==========================================================
 
     ___  ___     _      _____  ______       ____  ___ 
    / _ \/ _ \___| | /| / / _ \/_  __/ _  __|_  / / _ \
   / // / // /___/ |/ |/ / , _/ / /   | |/ //_ <_/ // /
  /____/____/    |__/|__/_/|_| /_/    |___/____(_)___/ 
                                                     
                       DD-WRT v3.0
                   http://www.dd-wrt.com
 
==========================================================


BusyBox v1.31.1 (2020-01-14 02:05:16 +04) built-in shell (ash)

root@160nl-switch:~# ps
  PID USER       VSZ STAT COMMAND
    1 root      1180 S    /sbin/init
    2 root         0 SW   [kthreadd]
    3 root         0 SW   [ksoftirqd/0]
    4 root         0 SW   [kworker/0:0]
    5 root         0 SW<  [kworker/0:0H]
    7 root         0 SW<  [khelper]
    8 root         0 SW   [kworker/u2:1]
   86 root         0 SW<  [writeback]
   89 root         0 SW<  [bioset]
   90 root         0 SW<  [crypto]
   92 root         0 SW<  [kblockd]
  104 root         0 SW   [khubd]
  124 root         0 SW   [kworker/0:1]
  131 root         0 SW   [kswapd0]
  132 root         0 SW   [fsnotify_mark]
  236 root         0 SW<  [deferwq]
  479 root       940 S    /sbin/hotplug2 --set-rules-file /etc/hotplug2.rules --persistent
  512 root      1860 S    watchdog
  534 root         0 SW<  [cfg80211]
  604 root         0 SW   [scsi_eh_0]
  605 root         0 SW   [usb-storage]
  640 root         0 SW   [kworker/u2:2]
  641 root         0 SW<  [kworker/0:1H]
  829 root      1384 S    syslogd -Z -L
  832 root      1384 S    klogd
  839 root      1232 S    dropbear -b /tmp/loginprompt -r /tmp/root/.ssh/ssh_host_rsa_key -p 22 -s
  863 root      2604 S    /usr/sbin/smbd -D --configfile=/tmp/smb.conf
  866 root      2384 S    /usr/sbin/nmbd -D --configfile=/tmp/smb.conf
  935 root      1820 S    wland
 1070 root       912 S    cron
 1079 root      4448 S    httpd -n -p 80
 1081 root      1548 S    resetbutton
 1092 root      1860 S    process_monitor
 1760 root      1300 R    dropbear -b /tmp/loginprompt -r /tmp/root/.ssh/ssh_host_rsa_key -p 22 -s
 1761 root      1384 S    -sh
 1763 root      1384 R    ps
root@160nl-switch:~# cat /var/samba/smbpasswd
mrjcd:1000:FB234959C0FD6533543B250A1F7B6542:0234139080B72E1F056B6BF6D01F1AFA:[UX         ]:LCT-00000001:
root@160nl-switch:~# cat /tmp/smb.conf
[global]
log level = 1
netbios name = 160nl-switch
server string = 
syslog = 10
encrypt passwords = true
preferred master = yes
use sendfile = yes
aio read size = 2048
aio write size = 2048
large readwrite = yes
security = user
mangled names = no
max stat cache size = 64
workgroup = 
bind interfaces only = yes
guest account = nobody
map to guest = Bad User
smb passwd file = /var/samba/smbpasswd
private dir = /var/samba
passdb backend = smbpasswd
log file = /var/smbd.log
max log size = 1000
socket options = TCP_NODELAY IPTOS_LOWDELAY SO_SNDBUF=262144 SO_RCVBUF=262144
read raw = yes
write raw = yes
oplocks = yes
max xmit = 65536
dead time = 15
getwd cache = yes
lpq cache time = 30
min protocol = NT1
max protocol = SMB2
printing = none
load printers = No
usershare allow guests = Yes
[160nl-switch]
comment = "160nl-switch"
path = "/mnt/sda1/"
read only = no
guest ok = no
valid users = mrjcd
force user = root
root@160nl-switch:~# exit
Connection to 160nl-switch.mrjcd.com closed.
mrjcd@Deb:~$ 

 both these have samba username & PW and only the 160NL has samba min protocol = NT1 just so I 
 can get at it with some oldass junk I still have :-)

I just don't know WTH 
 1231 root       828 S    usmbd -c /tmp/smb.conf -u /tmp/smb.db
 1232 root       856 S    usmbd -c /tmp/smb.conf -u /tmp/smb.db
is doing on the EA8500  :'(