The SPA500 Series phone goes to SOS Mode Recovery state when the firmware on the phone is damaged. This is typically caused by abnormal operation such as a power interruption while the phone is upgrading. SOS Mode Recovery is manifested by an S.O.S. PhoneInRecoveryMode message on the screen of the phone after it boots up. This can be fixed by recovering the firmware using the firmware recovery tool, and loading a new firmware to the phone.
This article aims to show you how to fix a SPA500 Series phone from the SOS Mode Recovery state.
Applicable Devices
SPA500 Series
Software Version
All
Recover a SPA500 Series Phone
Note: This article assumes that the phone is in the same IP segment as the computer used to recover the phone, as it should be. The device used in this article is a SPA504G.
WRONG advice. Firmware version must follow version of internal recovery loader. If loader version is 7.5.2b or older, even the firmware used for recovery needs to be 7.5.2b or older. No way to recover with latest (e.g. newer than 7.5.2.b) on it.
For loader version newer than 7.5.2b the firmware used for recovery needs to be 7.5.2b or newer.
Getting Started
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