I'd also recomend downloading the latest firmware for the phone as it does not appear in CCA. Odd's are your phones will take too long to boot as it's looking for firmware that isn't there.
show telephony shows:
load 525G2 spa525g-7-4-9c
How to....
setup your tftp server
http://tftpd32.jounin.net/tftpd32_download.html
Download the firwmare for the phone
http://www.cisco.com/cisco/web/download/index.html (I used SPA525G_7.5.4_FW.zip)
Unzip the file (spa525g-7-5-4.bin and spa525g-7-5-4-bt.bin) into the folder that your TFTP Server points to.
Make a folder for the 525G2
cd flash:/phones
mkdir flash:/phones/525G2
copy tftp flash:/phones/525G2
Enable the files to be delivered:
tftp-server flash:/phones/525G2/spa525g-7-5-4.bin alias spa525g-7-5-4.bin
tftp-server flash:/phones/525G2/spa525g-7-5-4-bt.bin alias spa525g-7-5-4-bt.bin
Tell the UC that this is the phone load you want delivered to the phones:
telephony service
load 525G2 spa525g-7-5-4-bt
(spa525g-7-5-4-bt includes Bluetooth and spa525g-7-5-4 doesn't, you can only pick one. I like to have both available)
Make sure that the ephone type is 525G2 on all the ephones that are 525G2. Mine were all setup as 525G too). Update all the ephones to change the types to 525G2. You can do a script to restart them as you update too...
ie.
ephone 7
type 525G2
reset
!
ephone 8
type 525G2
reset
!
ephone 9
type 525G2
reset
!
ephone 7
type 525G2
reset
!
ephone 8
type 525G2
reset
!
ephone 9
type 525G2
reset
Figuring out the CDP issue now . I'm having to tell each phone that it need to use the voice vlan. My fault to editing the CCA deliver to match existing vlans. I would have hoped that this would be an editable feature by now... Even worse that this phone and system have both been out for a long time and to not have any firmware for 525G2 available in the CCA is not nice!
Problem is seen when registering any 500 series phone to a CME on UC520 platforms. The problem only occurs when the ephone tag value for this phone registration is 56 or higher.