I am a complete newbie and had never owned or played with an iPhone till I got one this morning.
I got hold of a brand new OOTB 1st Gen iPhone which had 1.1.4.
I 'Restored' it (DFU mode) with official 2.0.1 FW.
I then used Winpwn to create a custom 2.0.1 (jailbreak/activate/unlock) FW and 'Restored' it (DFU mode).
I managed to get iPhone into DFU mode 2 out of 2 attempts !!!!!
It worked perfectly without any hitches.
As stated, till this morning I had never used or owned an iPhone - complete newbie !!!!
Over the last few days I had read up on how to best install 2.0.1 onto a 1.1.4 OOTB - taking note of other peoples errors/issues and suggestions by the moderators/senior members.
Also asked volkspost and rugburn a few questions - they were more than helpful - Big Rep to them !!
Basically, following the guides/tutorials on this forum and help from members, it can be done easily.