My experiences, troubleshoot and solution to many problems
I'll tell you about the way I have had to follow to make it work (sorry for my English).
For me it was completely impossible to get this to work even following every step... and I'm not a beginner in this matter...
First I installed TurkoCFW, even when I already had Bada 2.0, this was easy, selecting Full Download in Multi-Loader 5.67 and filling everything except Tune, ETC and PFS.
I began trying other older ROMs without any luck, concretely those that use Clockworkmod failed both to be used to install zip files (it recognized the SD Card but it said "this mobile is GT-I9000 and the file doesn't match...") and it also failed when I tried to restore a Clockworkmod Recovery point (I don't remember the error code, but it was some number).
I Also had problems since the very beginning because all of them uses a FOTA file to flash it, but, it was supossed that the phone will restart automatically in recover mode, but no way... at the end I found out that
I had to keep home button pressed for 3-4s to get inside this mode, just after the automatic reboot, because it seemed dead. I also discovered the key combination
END + Lock + Vol.Down to bypass the "black screen" and go again to Bada OS.
Afterwards I tried Carbon but to make it work I had to first tick "Change Bootloader" in MultiLoader, select your Bootloader Files Folder, Download it, and then, after the reboot. untick it and flash the FOTA file that you supply.
I also pasted the boot.img file and the zip Rom to the SD Card.
At this moment I had the TWRP Recovery environment, but the problem was that, in the Install menu, I couldn't do anything because it didn't recognized the SD Card (said 0Mb), so I went to Advanced->Terminal and made:
> cat /proc/partitions
and it listed all block devices, I figured out looking at the byte size what were the SD Card (8Gb = 77423....), it was something like "/dev/block/mmcblck1" and wrote:
> mount /dev/block/mmcblck1 /external_sd
then I went to Install menu again and I pressed Refresh and navigating to /external_sd I found the ROM zip, but, when I tried to install it, it complaints about not being capable to mount neither /data, nor /system. (tried to convert to EXT4... as you explained but it didn't worked until I did the following actions).
I went again to the Terminal utility (Advanced menu) and listing again the devices (cat /proc/partitions) I found one with aprx. 440Mb (4442345...) and another one with aprx. 900Mb (998686...) and I mounted the 400 one as:
> mount /dev/block/mmcblck0p1 /system
(I think it were mmcblck0p1 but maybe another...)
and the 900Mb as:
> mount /dev/block/mmcblck0p3 /data
(idem)
Now I went to Install menu again, found again the zip file in /external_sd and, finally, it worked!!
I don't know why I had this problems but maybe it can help others... Now I'll try to backup Google Services, Play Store... with Titanium Backup and then, uninstall it to try to gain some more free memory.
Thanks for your great work and good luck to everybody