This info from the phone load readme files for the signed loads. The signed loads will not work with anything lower than 3.1 and once installed you can not go back to an earlier version (i.e. an unsigned load).
Cisco now provides image authentication with its various IP phone protocols. The addition of image authentication prevents tampering with the binary image prior to it being loaded into the phone. Any tampering with the image causes the phone to fail the authentication process and reject that image. The image authentication occurs through signed binary files.
The P00305000101 and P00405000101 firmware releases do not use regular binary files as did previous releases but only use signed binary files. This step improves IP phone security on the Cisco IP Phone models 7910 and 7940/60. However, the use of signed binary files does not allow downgrading to an earlier software release.
Note: After the P00305000101 or P00405000101 firmware release is installed, you can replace it only with the same or newer release. All releases prior to the P00305000101 or P00405000101 firmware release will not function on this phone after this release has been installed.
Caution: If you revert the cluster to Cisco CallManager Release 3.1 or 3.2, the P00305000101 or P00405000101 firmware release will function on these Cisco CallManager versions. If you have a firmware image that is older than P00305000101 or P00405000101 that is identified as the default image, the IP phone will try to load the default image, will be unsuccessful, and will display file not found on the IP phone display. It will then log an error of file not found in the CCM event log, but the IP phone will continue to function by using the P00305000101 or P00405000101 firmware image that was previously installed on the IP phone.
Cisco will provide all defect fixes for Cisco CallManager 3.1 and 3.2 and 3.3 firmware loads in firmware load P00305000101 and P00405000101 and later.
Has anyone had any major problems with the P00305000xxx loads? Besides the one-way audio bug in 101, I have had no issues with these loads and this the big deal everyone is making about signed loads is sort of unnecessary. Numerous times, I've been told I am not permitted to upgrade their phone loads because of this fear (usually my Partners who we are doing the work for).
I've got 15+ customers on P00305000300 now and to my knowledge, have none of the bugs I use to run in to in 204, 214, 215, 700, etc.
Sorry for steering this off topic, but I am curious.
Were running the P503 load and have not had any problems with it. We avoided doing the upgrade to signed loads for a while - letting others be the testers. This allowed us to skip the P501 load that had the one way audio problem. Been using P03 since day after release.
Are you getting this error “Installer User Interface Mode Not Supported. The installer cannot run in this UI mode. To specify the interface mode, use the -i command-line option, followed by the UI mode identifier. The value UI mode identifiers...
The below trick might come handy when you have to add a new node to a cluster but you don't have or is unsure of the security password for the publisher. This procedure has been around for ages.
1) Login into the CLI of the Publisher.