This is info I just got today   09/20/21  :-) 
Had to recover after installing 'dd-wrt.v24-47474_NEWD-2_K3.x_mega.bin'
took just a bit but after: 
tftp 'dd-wrt.v24-14896_NEWD-2_K2.6_mini_RT-N12.trx'
tftp 'dd-wrt.v24-25974_NEWD-2_K2.6_mini.bin'
webif install 'dd-wrt.v24-25974_NEWD-2_K2.6_mega.bin'  (installing this over r25974 corrects its messed up ports 1 & 2)
webif install 'dd-wrt.v24-47381_NEWD-2_K3.x_mega.bin' (NO good if you ever do a reset)
Had to do recovery all again :-(
got it back on r47377

logs below :-|

Yea, running DD-WRT it has always shown as the Asus RT-N12B 
It is the RT-N12D1




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

DD-WRT v24-sp2 mega (c) 2015 NewMedia-NET GmbH
Release: 01/20/15 (SVN revision: 25974)

DD-WRT login: root
Password: 
==========================================================
 
 ____  ___    __        ______ _____         ____  _  _ 
 | _ \| _ \   \ \      / /  _ \_   _| __   _|___ \| || | 
 || | || ||____\ \ /\ / /| |_) || |   \ \ / / __) | || |_ 
 ||_| ||_||_____\ V  V / |  _ < | |    \ V / / __/|__   _| 
 |___/|___/      \_/\_/  |_| \_\|_|     \_/ |_____|  |_| 
 
                       DD-WRT v24-sp2
                   http://www.dd-wrt.com
 
==========================================================


BusyBox v1.23.0 (2015-01-20 04:04:08 CET) built-in shell (ash)

root@DD-WRT:~# nvram get DD_BOARD
Asus RT-N12B
root@DD-WRT:~# cat /proc/cpuinfo
system type             : Broadcom BCMD144 chip rev 1
processor               : 0
cpu model               : MIPS 74K V4.9
BogoMIPS                : 149.91
wait instruction        : no
microsecond timers      : yes
tlb_entries             : 32
extra interrupt vector  : no
hardware watchpoint     : yes
ASEs implemented        : mips16 dsp
shadow register sets    : 1
VCED exceptions         : not available
VCEI exceptions         : not available

dcache hits             : 2147483648
dcache misses           : 2684352477
icache hits             : 2147483648
icache misses           : 3154116545
instructions            : 2147483648
root@DD-WRT:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00020000 00010000 "cfe"
mtd1: 007d0000 00010000 "linux"
mtd2: 00642400 00010000 "rootfs"
mtd3: 00010000 00010000 "nvram"
mtd4: 00030000 00010000 "ddwrt"
root@DD-WRT:~# dmesg
Linux version 2.6.24.111 (root@dd-wrt.buildserver) (gcc version 4.1.2) #23546 Tue Jan 20 04:04:35 CET 2015
CPU revision is: 00019749
Found a 8MB ST compatible serial flash
Determined physical RAM map:
 memory: 02000000 @ 00000000 (usable)
Entering add_active_range(0, 0, 8192) 0 entries of 256 used
Zone PFN ranges:
  Normal          0 ->     8192
  HighMem      8192 ->     8192
Movable zone start PFN for each node
early_node_map[1] active PFN ranges
    0:        0 ->     8192
On node 0 totalpages: 8192
  Normal zone: 0 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 8192 pages, LIFO batch:1
  HighMem zone: 0 pages used for memmap
  Movable zone: 0 pages used for memmap
Built 1 zonelists in Zone order.  Total pages: 8192
Kernel command line: console=ttyS0,115200 root=1f02 rootfstype=squashfs noinitrd
Primary instruction cache 32kB, physically tagged, 4-way, linesize 32 bytes.
Primary data cache 32kB, 4-way, linesize 32 bytes.
Synthesized TLB refill handler (20 instructions).
Synthesized TLB load handler fastpath (32 instructions).
Synthesized TLB store handler fastpath (32 instructions).
Synthesized TLB modify handler fastpath (31 instructions).
PID hash table entries: 256 (order: 8, 1024 bytes)
CPU: BCMd144 rev 1 at 300 MHz
Using 150.000 MHz high precision timer.
console [ttyS0] enabled
Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
Memory: 25988k/32768k available (3490k kernel code, 6764k reserved, 1369k data, 188k init, 0k highmem)
Calibrating delay loop... 149.91 BogoMIPS (lpj=749568)
Mount-cache hash table entries: 512
NET: Registered protocol family 16
Generic PHY: Registered new driver
PCI: no core
PCI: no core
PCI: Fixing up bus 0
NET: Registered protocol family 2
Time: MIPS clocksource has been installed.
IP route cache hash table entries: 1024 (order: 0, 4096 bytes)
TCP established hash table entries: 1024 (order: 1, 8192 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
TCP reno registered
devfs: 2004-01-31 Richard Gooch (rgooch@atnf.csiro.au)
devfs: boot_options: 0x1
squashfs: version 3.0 (2006/03/15) Phillip Lougher
io scheduler noop registered
io scheduler deadline registered (default)
HDLC line discipline: version $Revision: 4.8 $, maxframe=4096
N_HDLC line discipline registered.
Serial: 8250/16550 driver $Revision: 1.90 $ 4 ports, IRQ sharing disabled
serial8250: ttyS0 at MMIO 0x0 (irq = 8) is a 16550A
PPP generic driver version 2.4.2
PPP Deflate Compression module registered
PPP BSD Compression module registered
MPPE/MPPC encryption/compression module registered
NET: Registered protocol family 24
tun: Universal TUN/TAP device driver, 1.6
tun: (C) 1999-2004 Max Krasnyansky <maxk@qualcomm.com>
et_module_init: passivemode set to 0x0
PCI: Setting latency timer of device 0000:00:02.0 to 64
eth0: Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller 5.100.138.9
PCI: Setting latency timer of device 0000:00:01.0 to 64
pflash: found no supported devices
bootloader size: 131072
nvram size: 32768
sflash: Filesystem type: squashfs, size=0x63b761
partition size = 6562816
Updating TRX offsets and length:
old trx = [0x0000001c, 0x000009d0, 0x0015dc00], len=0x0079a000 crc32=0xf67c4d94
new trx = [0x0000001c, 0x000009d0, 0x0015dc00], len=0x007a0000 crc32=0x71d77149
Done
Creating 5 MTD partitions on "sflash":
0x00000000-0x00020000 : "cfe"
0x00020000-0x007f0000 : "linux"
0x0017dc00-0x007c0000 : "rootfs"
mtd: partition "rootfs" doesn't start on an erase block boundary -- force read-only
0x007f0000-0x00800000 : "nvram"
0x007c0000-0x007f0000 : "ddwrt"
Broadcom Watchdog Timer: 0.07 initialized.
u32 classifier
    Performance counters on
    Actions configured 
Netfilter messages via NETLINK v0.30.
nf_conntrack version 0.5.0 (1024 buckets, 4096 max)
ctnetlink v0.93: registering with nfnetlink.
IPv4 over IPv4 tunneling driver
GRE over IPv4 tunneling driver
ip_tables: (C) 2000-2006 Netfilter Core Team
ClusterIP Version 0.8 loaded successfully
TCP bic registered
TCP cubic registered
TCP westwood registered
TCP highspeed registered
TCP hybla registered
TCP htcp registered
TCP vegas registered
TCP scalable registered
NET: Registered protocol family 1
NET: Registered protocol family 17
Welcome to PF_RING 3.2.1
(C) 2004-06 L.Deri <deri@ntop.org>
NET: Registered protocol family 27
PF_RING: bucket length    128 bytes
PF_RING: ring slots       4096
PF_RING: sample rate      1 [1=no sampling]
PF_RING: capture TX       No [RX only]
PF_RING: transparent mode Yes
PF_RING initialized correctly.
PF_RING: registered /proc/net/pf_ring/
802.1Q VLAN Support v1.8 Ben Greear <greearb@candelatech.com>
All bugs added by David S. Miller <davem@redhat.com>
decode 1f02
VFS: Mounted root (squashfs filesystem) readonly.
Mounted devfs on /dev
Freeing unused kernel memory: 188k freed
br0: Dropping NETIF_F_UFO since no NETIF_F_HW_CSUM feature.
device br0 entered promiscuous mode
device vlan0 entered promiscuous mode
device eth0 entered promiscuous mode
device eth1 entered promiscuous mode
br0: port 2(eth1) entering learning state
br0: port 1(vlan0) entering learning state
device br0 left promiscuous mode
device br0 entered promiscuous mode
device br0 left promiscuous mode
device vlan1 entered promiscuous mode
device vlan1 left promiscuous mode
br0: topology change detected, propagating
br0: port 2(eth1) entering forwarding state
br0: topology change detected, propagating
br0: port 1(vlan0) entering forwarding state
root@DD-WRT:~# uptime
 01:18:15 up 18 min,  load average: 0.00, 0.00, 0.00
root@DD-WRT:~# Connection closed by foreign host.
mrjcd@Fat-Deb:~$ 

  ##############################################

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

DD-WRT v3.0-r47377 mega (c) 2021 NewMedia-NET GmbH
Release: 09/07/21
Board: Asus RT-N12B

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


==========================================================


BusyBox v1.33.1 (2021-09-07 09:43:57 +07) built-in shell (ash)

root@DD-WRT:~# cat /proc/cpuinfo
system type             : Broadcom BCMD144 chip rev 1
processor               : 0
cpu model               : MIPS 74Kc V4.9
BogoMIPS                : 149.91
CPUClock                : 300
wait instruction        : yes
microsecond timers      : yes
tlb_entries             : 32
extra interrupt vector  : yes
hardware watchpoint     : yes, count: 4, address/irw mask: [0x0ffc, 0x0ffc, 0x0ffb, 0x0ffb]
isa                     : mips1 mips2 mips32r1 mips32r2
ASEs implemented        : mips16 dsp dsp2
Options implemented     : tlb 4kex 4k_cache prefetch mcheck ejtag llsc vtag_dcache dc_aliases ic_aliases userlocal perf_cntr_intr_bit
shadow register sets    : 1
kscratch registers      : 0
package                 : 0
core                    : 0
VCED exceptions         : not available
VCEI exceptions         : not available

root@DD-WRT:~# cat /proc/mtd
dev:    size   erasesize  name
mtd0: 00020000 00010000 "cfe"
mtd1: 007c0000 00010000 "linux"
mtd2: 00542c00 00010000 "rootfs"
mtd3: 00010000 00010000 "nvram"
mtd4: 000b0000 00010000 "ddwrt"
mtd5: 00010000 00010000 "nvram_cfe"
root@DD-WRT:~# dmesg
Linux version 4.4.283 (root@linux) (gcc version 11.1.0 (OpenWrt GCC 11.1.0 r16896+6-3c46ba053d) ) #11688 Tue Sep 7 09:46:01 +07 2021
prom_init:194
CPU0 revision is: 00019749 (MIPS 74Kc)
Found ST compatible serial flash with 128 64KB blocks; total size 8MB
found nvram at 7E0000
map 32K netgear cfe nvram at 7F8000
copy 32768 bytes as cfe nvram
Using bcma bus
Determined physical RAM map:
 memory: 02000000 @ 00000000 (usable)
Primary instruction cache 32kB, 4-way, VIPT, I-cache aliases, linesize 32 bytes.
Primary data cache 32kB, 4-way, VIPT, cache aliases, linesize 32 bytes
Zone ranges:
  Normal   [mem 0x0000000000000000-0x0000000001ffffff]
  HighMem  empty
Movable zone start for each node
Early memory node ranges
  node   0: [mem 0x0000000000000000-0x0000000001ffffff]
Initmem setup node 0 [mem 0x0000000000000000-0x0000000001ffffff]
On node 0 totalpages: 8192
free_area_init_node: node 0, pgdat 8053f320, node_mem_map 81007000
  Normal zone: 64 pages used for memmap
  Normal zone: 0 pages reserved
  Normal zone: 8192 pages, LIFO batch:0
pcpu-alloc: s0 r0 d32768 u32768 alloc=1*32768
pcpu-alloc: [0] 0 
Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 8128
Kernel command line: console=ttyS0,115200 root=1f02 rootfstype=squashfs noinitrd init=/bin/sh
PID hash table entries: 128 (order: -3, 512 bytes)
Dentry cache hash table entries: 4096 (order: 2, 16384 bytes)
Inode-cache hash table entries: 2048 (order: 1, 8192 bytes)
Writing ErrCtl register=00000000
Readback ErrCtl register=00000000
Memory: 26004K/32768K available (4350K kernel code, 461K rwdata, 964K rodata, 228K init, 389K bss, 6764K reserved, 0K cma-reserved, 0K highmem)
SLUB: HWalign=32, Order=0-3, MinObjects=0, CPUs=1, Nodes=1
NR_IRQS:128
CPU: BCM53572 rev 1 at 300 MHz
clocksource: MIPS: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 12741736309 ns
sched_clock: 32 bits at 150MHz, resolution 6ns, wraps every 14316557820ns
console [ttyS0] enabled
Calibrating delay loop... 149.91 BogoMIPS (lpj=749568)
pid_max: default: 32768 minimum: 301
Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
BRCM Errata: Enable CPU_WAIT
clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604462750000 ns
futex hash table entries: 256 (order: -1, 3072 bytes)
NET: Registered protocol family 16
PCI: no core
PCI: no core
PCI: scanning bus 0
PCI host bridge to bus 0000:00
pci_bus 0000:00: root bus resource [io  0x0000-0xffff]
pci_bus 0000:00: root bus resource [mem 0x00000000-0xffffffff]
pci_bus 0000:00: root bus resource [bus 00-ff]
pci 0000:00:00.0: [14e4:0800] type 00 class 0x050100
PCI: Fixing up bridge
pci 0000:00:00.0: reg 0x10: [mem 0x18000000-0x18000fff]
pci 0000:00:00.0: reg 0x30: [mem 0x00000000-0x000007ff pref]
pci 0000:00:01.0: [14e4:4347] type 00 class 0x028000
pci 0000:00:01.0: reg 0x10: [mem 0x18001000-0x18001fff]
pci 0000:00:01.0: reg 0x30: [mem 0x00000000-0x000007ff pref]
pci 0000:00:02.0: [14e4:4715] type 00 class 0x020000
pci 0000:00:02.0: reg 0x10: [mem 0x18002000-0x18002fff]
pci 0000:00:02.0: reg 0x30: [mem 0x00000000-0x000007ff pref]
pci 0000:00:04.0: [14e4:0835] type 00 class 0xffffff
pci 0000:00:04.0: reg 0x10: [mem 0x18004000-0x18004fff]
pci 0000:00:04.0: reg 0x30: [mem 0x00000000-0x000007ff pref]
PCI: Fixing up bus 0
clocksource: Switched to clocksource MIPS
NET: Registered protocol family 2
IP idents hash table entries: 2048 (order: 2, 16384 bytes)
TCP established hash table entries: 1024 (order: 0, 4096 bytes)
TCP bind hash table entries: 1024 (order: 0, 4096 bytes)
TCP: Hash tables configured (established 1024 bind 1024)
UDP hash table entries: 256 (order: 0, 4096 bytes)
UDP-Lite hash table entries: 256 (order: 0, 4096 bytes)
NET: Registered protocol family 1
PCI: CLS 0 bytes, default 32
squashfs: version 4.0 (2009/01/31) Phillip Lougher
io scheduler noop registered (default)
HDLC line discipline maxframe=4096
N_HDLC line discipline registered.
serial8250_init
Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
serial8250: ttyS0 at MMIO 0x0 (irq = 8, base_baud = 1250000) is a U6_16550A
brd: module loaded
pflash: found no supported devices
try to find cfe size up to 8388608
bootloader size: 131072
nvram size: 65536
bcmsflash: Filesystem type: squashfs, size=0x53e6a6
partition size = 5516288
Creating 5 MTD partitions on "bcmsflash":
0x000000000000-0x000000020000 : "cfe"
0x000000020000-0x0000007e0000 : "linux"
0x0000001ed400-0x000000730000 : "rootfs"
mtd: partition "rootfs" must either start or end on erase block boundary or be smaller than an erase block -- forcing read-only
mtd: partition "rootfs" set to be root filesystem
0x0000007e0000-0x0000007f0000 : "nvram"
0x000000730000-0x0000007e0000 : "ddwrt"
brcmnand: found no supported devices
nflash: found no supported devices
Creating 1 MTD partitions on "bcmsflash":
0x0000007f0000-0x000000800000 : "nvram_cfe"
create ctf proc
et_module_init: passivemode set to 0x0
et_module_init: txworkq set to 0x0
et_module_init: et_txq_thresh set to 0xce4
et_module_init: et_rxlazy_timeout set to 0x3e8
et_module_init: et_rxlazy_framecnt set to 0x20
et_module_init: et_rxlazy_dyn_thresh set to 0
robo attach
robo id 25
attach ctf for eth%d
_ctf_attach:attach eth%d
bind ctf to eth if
eth0: Broadcom BCM47XX 10/100/1000 Mbps Ethernet Controller 7.14.164.18 (r692288)
PPP generic driver version 2.4.2
PPP BSD Compression module registered
PPP Deflate Compression module registered
PPP MPPE Compression module registered
NET: Registered protocol family 24
_ctf_attach:attach wl0
Broadcom Watchdog Timer: 0.07 initialized.
u32 classifier
    Performance counters on
    Actions configured
Netfilter messages via NETLINK v0.30.
nf_conntrack version 0.5.0 (406 buckets, 1624 max)
nf_conntrack_rtsp v0.7 loading
xt_time: kernel timezone is -0000
gre: GRE over IPv4 demultiplexor driver
nf_nat_rtsp v0.7 loading
ip_tables: (C) 2000-2006 Netfilter Core Team
NET: Registered protocol family 17
bridge: automatic filtering via arp/ip/ip6tables has been deprecated. Update your scripts to load br_netfilter if you need this.
Bridge firewalling registered
8021q: 802.1Q VLAN Support v1.8
startup nvram driver
found nvram
found cfe nvram
check if nvram copy is required CFE Size is 32768
nvram copy magic is 48534C46
max nvram space = 65536
VFS: Mounted root (squashfs filesystem) readonly on device 31:2.
Freeing unused kernel memory: 228K
switch id 0
b5301x_common: found switch: BCM5325, rev 4
bcm_robo_config_vlan_fun vid=0, vlan->members=0x2f, vlan->untag=0xf 
bcm_robo_config_vlan_fun ports=0 1 2 3 5t 
bcm_robo_config_vlan_fun vid=1, vlan->members=0x30, vlan->untag=0x30 
bcm_robo_config_vlan_fun ports=4 5 
bcm_robo_config_vlan_fun vid=0, vlan->members=0x2f, vlan->untag=0xf 
bcm_robo_config_vlan_fun ports=0 1 2 3 5t 
bcm_robo_config_vlan_fun vid=1, vlan->members=0x30, vlan->untag=0x30 
bcm_robo_config_vlan_fun ports=4 5 
device br0 entered promiscuous mode
device vlan0 entered promiscuous mode
device eth0 entered promiscuous mode
device eth1 entered promiscuous mode
br0: port 2(eth1) entered forwarding state
br0: port 2(eth1) entered forwarding state
br0: port 1(vlan0) entered forwarding state
br0: port 1(vlan0) entered forwarding state
device br0 left promiscuous mode
device br0 entered promiscuous mode
device br0 left promiscuous mode
device vlan1 entered promiscuous mode
CTF: disabled
fast-classifier (PBR safe v2.1.6b): starting up
fast-classifier: registered
ip6_tables: (C) 2000-2006 Netfilter Core Team
device vlan1 left promiscuous mode
br0: port 2(eth1) entered forwarding state
br0: port 1(vlan0) entered forwarding state
random: nonblocking pool is initialized
root@DD-WRT:~# 
Connection closed by foreign host.
mrjcd@Fat-Deb:~$