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format flash: on new 128 MB non cisco flash card

wilbol12 asked
Last Modified: 2012-05-08

Trying to upgrade flash from Cisco 3845 64 MB flash card to non Cisco (SimpleTech) 128 MB flash card.
Router#erase flash:
Erasing the flash filesystem will remove all files! Continue? [confirm]
%Error erasing flash: (Invalid DOS media or no media in slot)
Router#format flash:
Format operation may take a while. Continue? [confirm]
Format operation will destroy all data in "flash:".  Continue? [confirm]
Enter volume ID (up to 64 chars)[default flash:]:

Primary Partition created...Size 7 MB
%Error formatting flash: (Format failure - First sector write)
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SteveNetwork Manager

any sandisk compact flash will work.. perhaps the problem is the SimpleTech brand ?


Actually,  I did the format flash: first.  Did that mess up the 128 Flash card?  I just went and bought a 4 GB SanDisk flash card.  Will the 3845 or 2821 router see it?  What is the correct way to format it so that I do not have this problem again?
SteveNetwork Manager

no.. the Maximum CF card size for the 3845 is 512mb and the max CF card size for the 2821 is 256mb

but doing what you did above is fine.. it wont destory the card normally.. (unless its faulty)..


Why does it cost so much to buy a flash from Cisco?  I bought the 4GB SanDisk at walmart for 25 bucs.
SteveNetwork Manager

because the flash is 'certified' to work.. the suppliers have been through all the rigourous testing etc.. so they charge more for it i suppose..


ok, why does SanDisk work and it is cheaper?
SteveNetwork Manager

phh.. dunno.. it just does.. :) you can always go genuine if you wanted ;)


I bought 2 Silicon Systems flash 512 MB and installed them on a 2821 and 3845.  512 MB will work on a 2821.  I was using 12.4(22)T on both routers.

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