[Xiaomi Redmi 3 Questions & Answers] Valdem:
Hi.

I tried to flash fastboot roms of next versions - 6.3.31 and 7.3.2.0. With "miFlash 2015.10.28.0" and "XiaoMiFlash(Beta)" (can't find version of this beta) and "QFil 1.0.0.2".

What I found during my investigation. That error happened so quick after start, it looks like software can't connect to device. I installed serial port sniffer to monitor activity of software on port, and I didn't see any traffic. Only few bytes during connecting device. I think that related to drivers. But I tried to do that on different PC with "Win7 x64" and "Win 8.1 x64" and tried with different drivers and of course disable signature checks during my attempts.

What I found in the log of miFlash:

[00000C60]COM20	0.13	Load programmer "C:\Temp\ido_7.3.2.0\images\prog_emmc_firehose_8936.mbn"
[00000C60]DownloadFlashProgrammerDMSS(625): An attempt was made to load a program with an incorrect format.(0x8007000b)
[00000C60]DownloadFlashProgrammer(930): An attempt was made to load a program with an incorrect format.(0x8007000b)
[00000C60]COM20	0.14	Open programmer "C:\Temp\ido_7.3.2.0\images\prog_emmc_firehose_8936.mbn"
[00000C60]COM20	0.14	Open serial port "\\.\COM20"
[00000C60]COM20	0.14	Receiving hello packet
[00000C60]COM20	0.14	Send hello response
[00000C60]COM20	0.14	EndTransferPacket id 0, status 9
[00000C60]DownloadFlashProgrammer(933): Unspecified error(0x80004005)

this I have when I start flashing first time after connection

and this after second attempt without reconnection:

[00000600]COM20	0.05	Load programmer "C:\Temp\ido_7.3.2.0\images\prog_emmc_firehose_8936.mbn"
[00000600]DownloadFlashProgrammerDMSS(625): An attempt was made to load a program with an incorrect format.(0x8007000b)
[00000600]DownloadFlashProgrammer(930): An attempt was made to load a program with an incorrect format.(0x8007000b)
[00000600]COM20	0.05	Open programmer "C:\Temp\ido_7.3.2.0\images\prog_emmc_firehose_8936.mbn"
[00000600]COM20	0.05	Open serial port "\\.\COM20"
[00000600]COM20	0.05	Receiving hello packet
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(209): Reached the end of the file.(0x80070026)
[00000600]DownloadFlashProgrammerSahara(781): Reached the end of the file.(0x80070026)
[00000600]COM20	2.23	Missed hello packet, try to recover
[00000600]COM20	2.23	Switch mode back
[00000600]COM20	2.23	Receiving hello packet
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(202): Reached the end of the file.(0x80070026)
[00000600]ReadRobust(209): Reached the end of the file.(0x80070026)
[00000600]DownloadFlashProgrammerSahara(814): Reached the end of the file.(0x80070026)