Step1:
Fist of all create tftp server in one of the updated IOS switch.
sw2(config)#tftp-server c2950-i6k2l2q4-mz.121-22.EA14.bin

Step2:
Then go to the remote switch where you want to upgrade IOS with new version.

sw1#copy tftp: flash:
Address or name of remote host [100.100.255.47]?
Source filename [100.100.255.47]? c2950-i6k2l2q4-mz.121-22.EA14.bin
Destination filename [c2950-i6k2l2q4-mz.121-22.EA14.bin]?
Accessing tftp://100.100.255.47/c2950-i6k2l2q4-mz.121-22.EA14.bin...
Loading c2950-i6k2l2q4-mz.121-22.EA14.bin from 100.100.255.47 (via Vlan2): !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
[OK - 3722814 bytes]

3722814 bytes copied in 143.124 secs (26011 bytes/sec)

Step3.
Check your copied IOS in the switch.

sw1(config)#do dir flash:
Directory of flash:/

    2  -rwx         864  Mar 01 1993 05:45:31 +05:45  vlan.dat
    3  -rwx       13499  Sep 23 2014 22:17:39 +05:45  config.text
    4  -rwx        1952  Sep 23 2014 22:17:39 +05:45  private-config.text
    5  -rwx     3722112  Mar 01 1993 07:33:24 +05:45  c2950-i6k2l2q4-mz.121-22.EA12
    6  -rwx        5871  Mar 01 1993 06:18:00 +05:45  sw1-config
    7  -rwx          43  Mar 01 1993 07:37:36 +05:45  env_vars
    8  -rwx     3722814  Sep 24 2014 12:30:41 +05:45  c2950-i6k2l2q4-mz.121-22.EA14.bin
  305  -rwx        5168  Mar 01 1993 08:37:25 +05:45  running-config1
  306  -rwx        1048  Sep 23 2014 22:17:39 +05:45  multiple-fs

7741440 bytes total (263680 bytes free)

Step5.
Verify the IOS if corrupted while copying form remote system to the destination system.

sw1#verify /md5 flash:c2950-i6k2l2q4-mz.121-22.EA14.bin
.............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................Done!
verify /md5 (flash:c2950-i6k2l2q4-mz.121-22.EA14.bin) = 8d3250ee253b81b7fe2762e281773fbc

Step6.
Now boot system

sw1(config)#boot system c2950-i6k2l2q4-mz.121-22.EA14.bin

Step7.
Write into the memory, otherwise your system may not boot from the new IOS or if you removed working IOS you system may not found any IOS.

sw1#wr memory
Building configuration...
[OK]

sw1#reload
System configuration has been modified. Save? [yes/no]: y
Building configuration...
[OK]

Step8.
Now check your system boot from new IOS

sw1#sh ver | inc image
System image file is "flash:/c2950-i6k2l2q4-mz.121-22.EA14"
Proceed with reload? [confirm]

How to recover extra space in 2950 switch.

In case you may have little space in switch, your new IOS have "3722814" size and switch only left "2220544" bytes free, in my case I don't need html file so I delete it form the switch.
sw1#dir flash:
Directory of flash:/

    2  -rwx     3722112  Apr 08 2013 11:13:12 +05:45  c2950-i6k2l2q4-mz.121-22.EA12
    3  -rwx         796  Mar 01 1993 05:45:28 +05:45  vlan.dat
    4  drwx        4224  Mar 14 2008 11:52:14 +05:45  html
   79  -rwx        1048  Sep 23 2014 17:05:12 +05:45  multiple-fs
   81  -rwx       12534  Sep 23 2014 17:05:12 +05:45  config.text
   83  -rwx        1958  Sep 23 2014 17:05:12 +05:45  private-config.text

7741440 bytes total (2220544 bytes free)

sw1#delete /f /r flash:html
Delete filename [html]? 

This tutorial assumed you already create Hotspot in your router. If you don't know how to create a hotspot in Mikrotik router, click here and create the Hotspot. .

After successfully creating the hotspot server go to "Files" Menu of  the main Window of Mikrotik router Copy "hotspot" folder into your PC.

1. The following instructions appear:
  The system has been interrupted prior to initializing the
   flash filesystem.  The following commands will initialize
   the flash filesystem, and finish loading the operating
   system software:
       flash_init
       load_helper
       boot
   switch:

2. Now follow the following command

switch: flash_init
switch: dir flash
switch: rename flash:config.text flash:config.old
switch: boot

3. Enter "n" at the prompt to start the setup program

--- System Configuration Dialog ---
   At any point you may enter a question mark '?' for help.
   Use ctrl-c to abort configuration dialog at any prompt.
   Default settings are in square brackets '[]'.
   Continue with configuration dialog? [yes/no]: n

    !--- Press Return or Enter.
 
    Switch>
 
    !--- The Switch> prompt is displayed.

      switch>en
      switch#

4. Type rename flash:config.old flash:config.text to rename the configuration file with its original name.

    Switch#rename flash:config.old flash:config.text
                Destination filename [config.text]
    Switch#

5. Copy the configuration file into memory

       Switch#copy flash:config.text system:running-config

6. Change the password


      Switch#configure terminal
      Switch(config)#no enable secret
      Switch(config)#enable secret Cisco
      Switch(config)#end

7. Write the into the memory.

          Switch#write memory
                 Building configuration...
                 [OK]
        Switch#

To reset password of  2970 Switch, power off the switch and press MODE button then power it on, take a look at the SYS led when it glows green leave the mode button. To recover the password click here.

Now your are in switch: prompt mode.
switch: flash_init
switch: dir flash:

switch: delete flash:config.text
switch: delete  flash:vlan.dat

 

Recently I encounter weird issue with JunOS. While Cold Booting the Juniper ex4200 switch its shows following message.
I do nothing just first boot the device thus face unknown reason message. Then I dig the google however some command doesn't work except below one. This JunOS version was 12.3.

sw1@jpudasaini>show system storage partition

Solution
EX
root>request system reboot slice alternate media internal 

SRX
root>request system reboot media internal 

Now reboot your device and the error message is already gone. To verify the which boot partition do used by your device use the following command.

Recently I encounter Cisco switch 3750 reload puts it into switch: prompt. I try every possible troubleshoot but wherever switch reload its automatically boot to recovery mode.

This is happen because manually boot process is enable to yes.

test-sw4#sh boot
BOOT path-list:       flash:/c2950-i6k2l2q4-mz.121-22.EA12
Config file:          flash:/config.text
Private Config file:  flash:/private-config.text
Enable Break:         no
Manual Boot:          yes
*************Output Omitted****************

To set switch to boot automatically, we have to issue no boot command in global configuration mode.

test-sw4(config)#no boot manual ?
  <cr>
test-sw4(config)#no boot manual
test-sw4(config)#end
test-sw4#wr
Building configuration...
[OK]
test-sw4#

Verify the command.

test-sw4#sh boot
BOOT path-list:       flash:/c2950-i6k2l2q4-mz.121-22.EA12
Config file:          flash:/config.text
Private Config file:  flash:/private-config.text
Enable Break:         no
Manual Boot:          no
HELPER path-list:  
*****************Output Omitted****************

Other method
You can set it form the switch:prompt
Initial might be look like this. MANUAL_BOOT=yes

switch:setBOOT=flash:/c2950-i6k2l2q4-mz.121-22.EA12MANNUAL_BOOT=yesswtich:

switch:MANUAL_BOOT=no

In this lab we learn to configure access server. For this lab we are going to use Cisco 2511 router. Before configure the access server make sure you have connect console cable to the router and you can access the router.

Access_Server#sh ver
Cisco Internetwork Operating System Software
IOS (tm) 3000 Software (IGS-J-L), Version 11.0(18), RELEASE SOFTWARE (fc1)
Copyright (c) 1986-1997 by cisco Systems, Inc.
Compiled Mon 01-Dec-97 17:59 by jaturner
Image text-base: 0x03034C58, data-base: 0x00001000

Access_Server uptime is 3 hours, 45 minutes
System restarted by power-on
System image file is "flash:igs-j-l.110-18", booted via flash

cisco 2511 (68030) processor (revision M) with 14336K/2048K bytes of memory.
Processor board ID 10355024, with hardware revision 00000000
Bridging software.
SuperLAT software copyright 1990 by Meridian Technology Corp).
 --More--

Command reference

hostname Access_Server
!
enable secret 5 (deleted)
!
username cisco privilege 15 password 7 (deleted)
!
interface Loopback0
 ip address 172.16.1.1 255.255.255.0
!
interface Ethernet0
 ip address 10.10.10.10 255.255.255.0
 !
interface Serial0
 no ip address
 shutdown
 no fair-queue
!
interface Serial1
 no ip address
 shutdown
!
ip host Sw1 2001 172.16.1.1
ip host Sw2 2002 172.16.1.1
ip host Sw3 2003 172.16.1.1
ip host Sw4 2004 172.16.1.1
ip route 0.0.0.0 0.0.0.0 10.10.10.1

line con 0
line 1 16
 transport input all
line aux 0
 transport preferred telnet
 transport input all
 rxspeed 38400
 txspeed 38400
 flowcontrol hardware
line vty 0 4
 no login

ip host: to mapped name-to-address of the static host
    ip host (name)[tcp-port-number][address]
transport input: define a input protocol on the async lines to Telnet
    transport input all

Verify the command

Access_Server>sh ip interface brief
Interface        IP-Address      OK?  Method    Status                 Protocol
Ethernet0        10.10.10.10  YES  manual    up                     up     
Loopback0        172.16.1.1      YES  manual    up                     up     
Serial0          unassigned      YES  not set   administratively down  down   
Serial1          unassigned      YES  not set   administratively down  down   

Access_Server#sh host
Default domain is not set
Name/address lookup uses domain service
Name servers are 255.255.255.255

Host                     Flags      Age Type   Address(es)
cust215-20.classic.com.np(temp, OK)  0   IP    49.236.215.20
Sw1                      (perm, OK)  0   IP    172.16.1.1
Sw2                      (perm, OK)  3   IP    172.16.1.1
Sw3                      (perm, OK)  3   IP    172.16.1.1
Sw4                      (perm, OK)  3   IP    172.16.1.1
Access_Server#

Troubleshoot:

 Access_Server#sw2
Trying Sw2 (172.16.1.1, 2002)...
% Connection refused by remote host

Access_Server#clear line tty 2
[confirm]
 [OK]
Access_Server#sw2            
Trying Sw2 (172.16.1.1, 2002)... Open

Amnesiac (ttyu0)

login: