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ASR9000/XR Understanding Turboboot and initial System bring up



This document provides an understanding of what Turboboot is and how to bring up a system running IOS-XR from scratch

There are two ways to upgrade the system:

  • One is to install add and activate the new XR software version. At a minimum this would require that mini.pie file
  • The second way is by performing a turboboot, fresh install, by booting the mini.vm file from rommon

This executable mini.vm file needs to be transferred via TFTP (on the RSP2) or can be loaded from the external USB port or TFTP (on the RSP440 and CRS-PRP). On the 9001 the USB ability is added in rommon 2.03 (5.1.1 release version).

No other media or protocols are possible to be used for a turboboot other then the ones specified above. Ex FTP is not allowed

File System overview

XR devices have multiple medias for storage and they all have their individual purpose.

disk0:Embedded USBSSD (SATA)  
disk0a:Embedded USBSSD (SATA)  
disk1:Embedded USBSSD (SATA)  
disk1a:Embedded USBSSD (SATA)  
harddisk:Harddisk (SAS)Embedded USB  
harddiska:Harddisk (SAS)Embedded USB  
harddiskb:Harddisk (SAS)Embedded USB  
compactflash:Compactflash1External USB1  
lcdisk0:  Embedded USBEmbedded USB
lcdisk0a:  Embedded USBEmbedded USB
bootflash:NOR Flash NOR FlashNOR Flash
configflash:NOR Flash   
Kernel dumpHarddisk (SAS)SSD (SATA)TFTPbootflash:
 1. Removable   
Access (Mount) Points (in /dev)
disk0:disk00t77hd0t77qsm to active rspqsm to active rsp
disk0a:disk00t78hd0t78qsm to active rspqsm to active rsp
disk1:disk10t77hd1t77qsm to active rspqsm to active rsp
disk1a:disk10t78hd1t78qsm to active rspqsm to active rsp
harddisk:hd0t79usb00t77qsm to active rspqsm to active rsp
harddiska:hd0t77usb00t78qsm to active rspqsm to active rsp
lcdisk0:  lcdisk00t77lcdisk00t77
lcdisk0a:  lcdisk00t78lcdisk00t78
bootflash:fs0p1 fs0p1fs0p1
Kernel dumphd0t80hd0t80 or hd1t802 fs0p2
 1. Any one2. Either one  
disk0:IOS-XR Packages, ConfigsIOS-XR Packages, Configs  
disk1:IOS-XR Packages (if Mirrored)IOS-XR Packages (if Mirrored)  
harddisk:Crash files, logsCrash files, logs  
harddiska:NP logs, crash filesNP logs, crash files  
compactflash:File CopyFile Copy  
lcdisk0:  Kernel dump filesKernel dump files
bootflash:MBI Images   
Kernel dumpRaw kernel dumpsRaw kernel dumps Raw kernel dumps
lcdisk0:  QNX4QNX4
lcdisk0a:  QNX4QNX4
bootflash:FFSv3 FFSv3FFSv3
Kernel dumpRawRawFileRaw
 1. FAT F/S only2. Flash Media only  
Approximate Parition Size (minimum)
lcdisk0:  1.6GB1.6GB
lcdisk0a:  0.4GB0.4GB
bootflash:44MB 56MB56MB
Kernel dump21GB500MB x 2 24MB

Note that unlike many IOS devices, nvram is NOT used for the configuration storage. Configurations are stored in a database on the boot disk (often disk0). Typically only rommon variables and license info are stored in nvram.

Summary steps for using turboboot

Because a  turboboot can erase configuration, SSH keys, and other items such as  licenses the following should be done to check and backup any files

1. Run a cfs check in admin & non-admin mode

2. Copy active licenses and SNMP files to tftp server

3. Copy running config to a tftp-server or laptop

4. Capture "show ipv4 int brief" output to a text file

5. Capture "show ipv6 int brief | i Up/Up" output to a text file

6.  Offline. Edit the saved RSP config - add "no shutdown" for all physical  interfaces that are up/up from the above IPv4 & IPv6 interface  captures and save cfg changes. Note that it is not necessary to “no  shut” sub-interfaces, only the main physical interface.

7. Connect a laptop console cable to the RSP in RSP0 slot and enable a log file to monitor and capture the RSP bootup logs.

8 . Turn the power supplies on to power up the asr9k system. (approx. 7-12 minutes)

9.  After the LED's indicate IOS-XR on the LC's, and ACTV or STBY on the  RSP’s, log in via the console of the RSP that is ACTV and run some  preliminary checks to check system stability.

NOTE: The default root-system username and password on the RSP440 are root/root

(if root/root does not work also try cisco/cisco, or admin/admin or viking/viking)


10. Verify the ASR9K IOS XR version

11. Run a cfs check in admin & non-admin mode

12. (Optional) Install add & commit any missing SW packages (pies) or required SMU’s

13. Upgrade FPD in admin mode

14. Reload any nodes that had FPD upgrades

15.  Configure the Mgmt ethernet interface with an IP address to reach tftp  server & load and commit the saved RSP config from tftp server or  laptop

a) or log into the console and cut & paste a saved cfg from laptop

b) or copy saved cfg from laptop to usb, then insert usb into RSP440 and copy and commit cfg

c) copy licenses and snmp files back to the RSP’s

16. (Optional) create and generate new crypto keys if required.

Steps to Turboboot


As mentioned Turbobooting means that you load the "VM" (virtual machine) XR base OS image.

Turboboot is started from Rommon and is essentially the same as putting a disk with the desired OS in your laptop, reboot the machine to boot from CDROM, and installing the base OS.

Before the Turboboot process starts, you can instruct the system to wipe all files from the system and start clean or install the image to be turbobooted along side with any existing releases currently found on the disk. (see Set the Turboboot variables on the RSP)

Turbobooting may be required if you want to sweep clean your system, or we also had some issues in XR4.2.0 with the RSP2 whereby the upgrade pie could not be loaded. A turboboot was required in that case also.

Some or all of these procedures below are needed.

The command "set" gives you an overview of all the rommon environment variables currently set to their values.

Clear the ROM Monitor environmental variables on all RSPs

unset BOOT

the command *unset* clears the variable value from rommon.

the command *sync *saves or writes the newly set and unset variables to persistent memory so they are saved cross reloads and power cycles.

Clear disk mirroring variables


By default, the two internal USB partitions (disk0 and disk1) are mirrored to each other, if you break the mirror, turboboot will only affect the disk

that you are turbobooting target to and not the other one (nice if you want to fall back).

Disable the CPU watchdog

diswd <- Disable the CPU watchdog

If you omit this step and the TFTP download for the turboboot mini-vm image takes longer than 30 minutes due to network delays etc, then the RSP might reset and you'll have to start over. Disabling this watchdog makes sure the system is not going to reload during the transfer of the image in rommon.

Define the network and IP settings on the mgmt interface


Set TFTP environment variables


sets the number of retries to contact the tftp server


sets the TFTP timeout for the transfer, you may need to set this larger to prevent abort during xfer if there are network delays


whether checksum on the transfer is needed, this is adviceable in case the image gets corrupted during transfer.


the server address can also be specified in the boot statement, or fixed in the rommon variable.


which of the 2 mgmt interfaces you want to use, either 0 or 1 with 0 being the default.


Setting a larger TFTP block size is recommended to pack larger packets and transfer the VM image quicker. Note that for CRS this variable is TFTP_BLOCK_SIZE.

Set the Turboboot variable on the RSP

TURBOBOOT=on, {boot-device},[format | clean],[nodisablebreak]

on tells us to install add and install activate the packages when we boot from the VM image.

boot-device is which device we want to use to install the OS, typically disk0

format tells us to replace the OS completely except for the admin configuration

clean tells us to replace the OS completely, but other files such as the admin or exec configuration are saved

nodisablebreak allows us to terminate the turboboot via a break signal. The default is to ignore breaks



This will instruct the system to do a turboboot with disk0 as the selected boot device and to use the format option. The format key is optional.

Currently today we only support targeted install to disk0 but this will change likely in XR4.3.1 whereby you can use disk1 as install target.

NOTE: a recent tac case showed that the command for turboboot failed on the ASR9001.

Supposedly this was made to work by omitting the colon after disk0:

Suggesting to try the disk0 (without colon) if the command with colon fails.


ASR9K/CRS-PRP Additional Information


In CRS the format option works with FAT16 but not FAT32 or QNX4 so a new variable must also be used.

In ASR9K the format and clean options do work but in order to erase the exec configuration, admin configuration, and every other file this additional variable must be used.


For these scenarios the following must be set.




Note: If the format or clean options are set in turboboot or confreg 0x2142 is set when also having the MEDIA_FORMAT variable set then when prompted for a new username/password we will be unable to write this to the disk. To fix this go back to rommon and properly set the variables.


Boot the remote mini.vm file

(Works only with the VM image, not the TAR file or mini.pie)

rommon> boot tftp://server/directory/filename

During the boot process the image is copied first on to the memory(RAM) and is installed from memory(RAM). Once it is insalled from memory, it will copy the image back on to disk0: and reload the device. Wait till you get the message "SYSTEM CONFIGURATION COMPLETED"

Output of show install active when in memory,

RP/0/RSP0/CPU0:ios#sh install active
Active Packages:

Output of show install active after image copied on to disk0:,

RP/0/RSP0/CPU0:ios#sh install active
Active Packages:

The system will also self unset the TURBOBOOT rommon variable.

Restore disk mirroring

To restore disk mirroring, use the mirror command in the global configuration mode. For more information on the mirror command, see the "Boot Commands on Cisco IOS XR Software" module in Cisco ASR 9000 Series Aggregation Services Router System Management Command Reference.

How to boot from the external USB port

The RSP-440 (and 9001 with rommon 2.03) can boot from the USB front panel port. Instead of using "boot tftp:// or boot disk0:/" you need to use a different command, mediaboot.

The command is:

rommon> mediaboot usb:\release_mini.vm

In later revisions of the rommon, the mediaboot has been superseded to boot usb:/<file>

so make sure you try them both.



Some newer rommon versions on the 9001 want to use the boot usb:/ directive. (see Q&A/comment section below this article).

It is also seen in rommon versions post 2.04 that the usb is referred to as disk1 in which case you can use: boot disk1:/...

To find out the mapping of the usb disk use the rommon "dev" command to see all filesystem devices.


On the CRS-PRP use boot disk2:hfr-mini-px.vm<image>

CRS does not use the mediaboot command.

How to update the FPD's

FPD upgrade for all ASR9K devices using FPD.

a) Enter admin mode via the admin command, and capture the output of the current firmware versions using CLI show hw-module fpd location all. save this output to a text file. Notice any LC that has a “yes” in the Upg/Dng?  column. This indicates the FPD should be upgraded or downgraded to match the current FPD version.

b) From admin mode upgrade FPD using the CLI: upgrade hw-module fpd location r/s/m

or if all locations require FPD upgrade (suggested) use CLI:* upgrade hw-module fpd location all *

Disk Space occupied for each image

Simplest way is to use the ksh df utility.

Install a release and packages and run df:

# df /disk0:

/dev/disk00t77           3813344    733477   3079867      20%  /dev/disk0:/   

Divide the highlighted number by 2000. That gives the approximate size in MB. 366MB in this case.

Repeat for any other releases we should be interested in.

If you do an upgrade, gather the df output before and after upgrade and compute the difference in df output.

Related Information

Xander Thuijs, CCIE #6775

Principal Engineer ASR9000

Sam Milstead,

Customer Support Engineer TAC XR


Hello Xander Thujis,

Thanks for the detailed explanation regarding turboboot procedure. I have followed the above steps for downgrading 4.3.1 to 4.2.3. The VM file size is about 330Mb. TFTP operation is getting terminated after some point of time. Im using 3Cdeamon server and has configured max timeout and retries already. Is there anything Im missing here.

Appreciate your quick response.



Cisco Employee

Have you tried to set the TFTP_BLK_SIZE to 1400 in rommon?

also due to the image combo (of p and px in 43) downgrading to 42 can be tricky. you may need the turboboot option with the disk0,format option also.




rommon B40 > set

PS1=rommon ! >





















I have tried changing MGMT_INTF, CHECKSUM=0, BLKSIZE=1400 etc.

TFTP gets terminated after copying about 150Mb. Total VM size is 330Mb

Cisco Employee

Please try to disable the download watchdog from rommon:



also it may help to pull out the standby RSP, it may be impatient also.



I had disabled watchdog, but still it was not happening with 3cdaemon. I changed to solar winds and the image has been copied without any interruption. I have successfully completed the downgrade.

Once again, thanks for posting this document.



Cisco Employee

ah great, thanks for letting me know and for your nice comment, appreciate it!





Is the integrated RSP in the 9001 equiv to the filesystem representation charts above for the RSP2 or is it different?

Cisco Employee

the disk sizes are slightly different for 9001, but the filesys layout is pretty much the same.



Is there a method for uploading the vm image in advance to Disk0: and performing the upgrade from there? If so, how do the rommon arguments need to be modified to facilitate that?


Cisco Employee

great question adam, but no unfortunately, this wont help:

the disk0/1 is the internal usb disk and rommon doesnt have drivers for it.

this means that in rommon (for turboboot) you have access to tftp and bootflash, so the image has to fit there for the vm turboboot.

the usb front port on the RPS440 is accessible out of rommon btw.




That's a bummer.

Thank you for this entire write-up Xander. It has been most helpful.



Appended a small content to calculate the disk space occupied for each image.

Cisco Employee

Fantastic document Xander! very informative just what I needed.

Much Appreciated.. will try these optimal settings and see if we can get out of rommon!


I spent a day and a half trying to get an ASR9001 stuck in ROMMON to boot an image via TFTP. Finally got it to work!!!!! The winning combination (for me at least) is to set the TFTP_BLKSIZE=1024 and to use Solarwinds Free TFTP server. Also make sure you dont have any firewalls blocking the TFTP traffic on UDP 69.

Cisco Employee

hi simon, thanks for the detail but sorry to hear you wasted so much time...!

good news is that coming soon the usb port for the asr90001 will be made to work, so that saves a lot of trouble.

also the diswd (disable watchdog) can help in preemptive timeout/reloads.

yeah that firewall unblock will help too