upgrading latest firmware preserving the baseband 6.15.00 in 3gs

[medxx]

well, i have 3gs running in 4.1 firmware with the baseband 6.15.00 (ipad bb) and i want to upgrade my firmware to the latest provided by itunes.
well how can that be done without losing my baSEBAND???
i just wanted to know
1. the best programme to do the upgrade without losing baseband
2.the advantages of upgrading
3. the firmware versions to which if i upgraded then i wont lose my unloock
4.the disadvantages of upgrading


i know these might have been asked to u a million times...sorry for that! i wanted to take you guys opinion before doing anything to my phone ....

thanks in advance
regards
medxx

[thecrunked]

1. sn0wbreeze for pc, pwnagetool for mac

2. not much really, some bug fixes, some apps/cydia packages are not compatible with 4.1

3. 4.3.2, the latest

4. having to reinstall all of your stuff

[medxx]

thanks for the info !!