Personally, I'd avoid using any NT-based kernel OS for this kind of work as the OS loves to take charge of the ports and the software you use may not be compatible as such. I know this is especially the case with DOS-based flashers like Dejan Flasher, which is what I use as part of the flashing process.
Install a dual boot with Win98 (2nd edition for reliability - what an oxymoron that is!) as your 2nd OS and do it all from there.
Secondly, don't use Dejan Flasher to do a full backup of your phone before you commence the operation. It won't tell you you're using the wrong f_loader.bin file when you're reading your phone. This could prove to be disastrous as it was for me when I decided to go back to my 6210 s/w after I found I was having some bugs with the "Names" button from the main screen and my voice recognition was freezing when it was looking for a match. I was using f_loader.bin from the loader01 directory when it should have been from loader02 (since that's what was required for the writing process). Anyway, when I performed the restoration of the backup I made in Dejan, it then refused to switch on. When I then performed a 6210 s/w install using the v5.56 MCU+PPM and the 6210 Virgin EEPROM found on the net, I kept getting "Contact Service" on the screen. Since then, I've discovered that was because the 6210 Virgin EEPROM was a faulty one.
I used Rollis Flasher to make a complete backup of my friend's 6210 and copied it into my phone to bring it back to life. For some bizarre reason, my phone would reject SIM cards after I restored the 6210 software (which wasn't happening with my friend's phone because he was lock free). I then fired up kNok and did the "Quick Set FAID -> Set new IMEI -> Quick Set FAID -> Reset Phone" procedure. I soon discovered (using Nokia Tool 0.34) that I had FFFF's in all my Service Provider locks. I fired up kNok and selected "Reset SP Locks" and all was well again. I then SW reset the phone, closed kNok, applied the special SFS fix in Nokia Tool 0.34, SW reset the phone again and all has been well since.
Then I thought I'd be daring and reinstall the 6250 s/w using v5.03 MCU+PPM with Rollis Flasher and the 6250 Virgin EEPROM with Dejan Flasher (using the f_loader.bin file from the loader02 directory). Then I did the same as the above, more or less. I started kNok, did the Quick set FAID/IMEI procedure as noted above, reset the phone, closed kNok, fired up Nokia Tool 0.34, applied SFS, sw reset and all has been well since apart from the one bug I had experienced the first time around....
The phone still takes an unusually long time to fire up (I'm using the R language pack, being an Australian issued phone) - I hold the power button for 2 secs, release it and then it reacts about 5 secs later on its own!!
The voice recognition now works since the reflash because I've wiped out all the voice tags and started fresh and it has retained the longer 10-character Profile names (if I simply wiped it all out to factory settings and installed the 6250 software, the Profile names were cut short to a maximum of 9 characters instead of the 10 I was used to with the 6210 s/w).
So all in all, it was quite an adventure for me!
To summarise:
FIRST, take your SIM card OUT of the phone, just in case. Using your DLR-3P cable (or infrared interface), use the Backup/Restore program supplied with your 6210 to keep a copy of your Phonebook, Messages, Profiles, Ringtones, Settings, Clock, etc.
Let the flashing begin!
A) Using Flasher cable (the parallel port interface):
1) Load up Rollis Flasher. Check the Phone Type is 6210. Backup your phone from 00200000 to 00600000 (just hit the first green button on the program's toolbar for a "Default Read" and when done it will ask you for a filename to save it to). Once completed, put the file in a safe place, remove the battery and reinstall the battery.
2) If you received your MCU and PPM files separately, copy them together as one file by going into DOS and typing the following at the prompt: "copy <mcu filename> /b + <ppm filename> /b <nominate your full flash filename> /b"
This will take the first 2 named files in their raw binary format and copy them as one large file which is the 3rd one you've typed in. Make sure you type the filenames in that specific order or you will have a bad flash!
3) Using Rollis Flasher and making sure the Phone Type is still 6210 again, this time hit the red button to load up your single full flash. It will ask for confirmation that you want to use this flash file in a different phone, hit OK, then it will ask about flashing addresses, just leave them alone and hit OK again.
4) Once procedure is complete, close Rollis Flasher, remove the battery and replace the battery.
5) Load up Dejan Flasher, making sure you have both your f_loader.bin file (from the loader02 directory) and your Nokia 6250 Virgin EEPROM in the C:\NK_FILES\ directory.
6) If you have done the above, you will be able to then hit F2 (to write to phone), select 6210 for your phone type, then your Virgin 6250 EEPROM filename will appear in another box. Select this and it will then ask you what the start address is. Enter "005A0000" and hit enter. The flash should take only a matter of seconds as opposed to the last long flashing of your MCU+PPM. Once this is done, exit Dejan Flasher (hit ESC). Remove and replace battery.
B) Using FBUS/MBUS cable (DAU-9 equivalent - do NOT use DLR-3 or its equivalents!):
7) Switch phone on
8) Load up kNok, choose the correct model phone (Nokia 6250 in this case) and then look in the "Phone Settings" menu. Select "Quick Set FAID". Then select "Set New IMEI", type in your IMEI number (your 6210's original IMEI is fine and probably won't get you into any legal trouble! :D ), select "Quick Set FAID" again, then select "Reset Phone". Do NOT reset to factory defaults as this may be detrimental to your 1800MHz band's performance.
9) Close kNok and load up Nokia Tool (at least v0.34). Select "Read ME". You should see your new IMEI and SP locks come up on your PC. If the SP locks are open, skip procedure 10. If not, perform procedure 10 as well.
10) Close Nokia Tool 0.34, load kNok, choose the correct model phone (Nokia 6250), go to "Modify Locks" menu and select "Reset SP lock". Select "Reset Phone" from the "Phone Settings" menu. Close kNok and load up Nokia Tool 0.34 and hit the "Read ME" button again. The information should come up again with all SP locks showing as "OPEN".
11) Place a tick in the tickbox beside "Device Data" in the "Special Factory Set" section of the program. Then hit "Apply SFS" and then "SW Reset".
Put your SIM card back in AND THAT'S IT!
You should still have your phone's original settings for welcome logo screens, caller groups, phone memories, profiles, ringtones and general call and phone settings, etc.
But if not, big deal. Using your DLR-3P cable again (or infrared), load up Logomanager to restore your graphics and use the Nokia 6210 backup/restore software to bring back all your other phone memories and settings. If it should stop communicating during any part of the restore process, just deselect the sections that have been restored successfully and resume the restore from the first item it failed with.
Enjoy!