Continues restart after enabling DFS on RB133 ROS 3.13

this is the third time I face this problem.just after a trivial change I get continues restart of RB. previous cases were RB433 and RB493.I cannot remember the changes I did these two. but on RB133 I just enabled DFS(dynamic frequency selection).after bringing down the box from a hardly reachable place and connecting through serial_just like previous cases_I received this error:

RouterBOOT booter 2.12

RouterBoard 133

CPU frequency: 175 MHz
  Memory size:  32 MB

Boot configuration CRC error, applying defaults
writing settings to flash... OK

Press any key within 2 seconds to enter setup.

RouterBOOT-2.12
What do you want to configure?
   d - boot delay
   k - boot key
   s - serial console
   o - boot device
   u - cpu mode
   r - reset configuration
   e - format nand
   g - upgrade firmware
   i - board info
   p - boot protocol
   t - do memory testing
   x - exit setup
your choice:


RouterBOOT booter 2.12

RouterBoard 133

CPU frequency: 175 MHz
  Memory size:  32 MB

Press any key within 2 seconds to enter setup..
loading kernel from nand... OK
setting up elf image... OK
jumping to kernel code
Starting...
Starting services...




MikroTik 3.13
MikroTik Login: Trap instruction in kernel code[#1]:
Cpu 0
$ 0   : 00000000 10008c00 80ca7898 00000003
$ 4   : 81444200 00000000 00000000 00000000
$ 8   : 00000000 801fbfd0 80334b4c 81028880
$12   : 00000001 80334b78 80365d80 00000000
$16   : 81444000 81790000 81444000 00000000
$20   : 00000000 80cbc000 00000016 00000000
$24   : 81e41c00 000186a0
$28   : 81e40000 81e41d08 05f5e100 817282a4
Hi    : 05f5e100
Lo    : ffffffff
epc   : 81728320 radar_enter+0x4e8/0xa98 [ath]     Tainted: P
ra    : 817282a4 radar_enter+0x46c/0xa98 [ath]
Status: 10008c03    KERNEL EXL IE
Cause : 10800034
PrId  : 0001800b (MIPS 4Kc)
Modules linked in: a5212_pci(P) bridge2 llc a5212(P) ath(P) wlan(P) fancon(P) rx
Process wireless (pid: 819, threadinfo=81e40000, task=81f32860)
Stack : 80c5fe40 81e41dd8 81e41db8 00000040 81e41d2c 81e41d34 81790014 8024ba10
        80ca7898 80ca7200 00000037 00000001 00000000 81790014 81739210 81739208
        00000000 80cbc000 0000000b 00000008 81739210 0000002c 81739208 81739208
        10005784 8151746c 00000000 00000000 0000000b 00000008 81739210 80c4ad80
        80cbc000 815327e4 00000010 00000000 00000008 00000000 0000000b 815177a0
        ...
Call Trace:
[<81728320>] radar_enter+0x4e8/0xa98 [ath]
[<8151746c>] w_hwdev_stateswitch+0x20c/0x374 [wlan]
[<815177a0>] w_ctl+0x1cc/0x15bc [wlan]
[<81509134>] w_netdev_rx+0x27c/0x79c [wlan]
[<802565e0>] dev_ioctl+0x6a0/0x730
[<8018b72c>] do_ioctl+0x2c/0x78
[<8018ba44>] vfs_ioctl+0x2cc/0x2fc
[<8018bac4>] sys_ioctl+0x50/0x8c
[<8010d0d0>] stack_done+0x20/0x3c


Code: 8c45000c  8c430028  03c5001b <00a001f4> 8c420014  00032100  00031880  006
Kernel panic - not syncing: Fatal exception in interrupt

panicSaver: dumping panic to flash
flash: erase 1c
flash: prg 1c
flash: prg err 0
Rebooting in 1 seconds..

RouterBOOT booter 2.12

RouterBoard 133

CPU frequency: 175 MHz
  Memory size:  32 MB

Press any key within 2 seconds to enter setup

And why not using 3.25? cuz when i install 3.25 on rb133 cpu load reaches 100% and throughput decreases by 3Mbps. there is no such problem on 3.13

Have you tried v2.9.51 ? And upgrade your bootloader too. This device is rather old, and newest versions could be too much for it in some configurations