I need the flash for: Nokia 1661-2 RH-122 v3.70
Besides the flash for: Nokia 2760 RM-258 v6.82

1. For the 2760 in the support site of GTS the versions of lower flash appear.
I can do a downgrade to the Nokia 2760 version 6.82 and to put him this RM-258_dp_11.43__sw-05.62.rar (Size: 109,46 mb) ????
Seeing attach image.

2. The nokia 2760 is a DCT4 + or BB5??? I ask this because support site of GTS the 2760 they appear in Nokia Flash Files and Nokia BB5 Flash File

3. Please I need that they help me to know that is the DP in the name of a Flash
Example: RM-258_dp_11.43__sw-05.62.rar (Size: 109,46 mb)
RM-258 - Identifying of the telephone
dp_11.43 - What signifies???
Sw-05.62 - Version of the software???
Size: 109,46 mb - so Great of the file

4. Now, which is the difference among:
folder Nokia Flash Files appears - RM-258_dp_10.19__sw-03.62.rar (Size: 88,17 mb)
folder Nokia BB5 Flash Files appears -
RM-258_dp_09.00_ams_sw-03.62.rar (Size: 57,99 mb)

the DP? ??? What signifies???