Per the readme.txt file:
Please follow the upgrade procedure
1. Please check HW version on device UI first.
2. Select a correct firmware version and upgrade method.
- If your device is A3 or B2 platform, please directly upgrade v3.11 common firmware
- If your device is A2 or B1 platform, Please upgrade v3.11 intermediate firmware first,
then upgrade v3.11 common firmware.
The DSR-250 being upgraded in hardware version A3. Per the instructions that were given as above, " If your device is A3 or B2 platform, please directly upgrade v3.11 common firmware". The intermediate step is only for hardware versions A2 or B1.
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