This information was originally posted by red321 on disQworld. Thanks to that fine forum for permission to reproduce here.

Sony Drives
I though it worth bringing together a lot of information on the Sony drive, which is scattered through a number of threads, and is often requested. It is really hard work to piece together the whole story, and seperate Fact from Fantasy. I have read this forum for the last 6 months, and tried all of this myself, so this is how it is:

The U10A, U12A,500a and 500ax are all basically the same drive, and the Firmware is interchangeable. The only restriction is introduced by the Flasher software, which checks that the identity of the drive matches the upgrade. This means that flashing between a U10A/U12A and a 500a/ax firmwares requires hacked firmware flashers. For some odd reason the same is required to flash from 1.1c to 1.1e of the U10A firmware. The 1.1e upgrade will only upgrade the 1.1a U10A firmware without "tweaking"

Before you start changing Firmware, make sure you need to. I see a lot of people desperately flashing their drives, without even bothering to find out what the advantages of the new firmware might be. Remember that you could lose your waranty if you flash from one series of drive to another and the drive dies.

Also 1.1a, 1.1d and 2.0c appear to be only available on new drives, no flasher to these versions is available. So if you move away from these firmwares, there is no way back.

The new 510 drives apear to be diffrent hardware and not interchangeable

What should my firmware do:

U10A firmware:

1.1a 4x DVD-R:2.4x DVD+R (1x on Ritek G03)
1.1c 4x DVD-R:2.4x DVD+R (2x on Ritek G03)
1.1e 4x DVD-R:2.4x DVD+R (2x on Ritek G03)

500a/ax firmware:

1.0d 4x DVD-R:2.4x DVD+R (1x on Ritek G03 BUT sometimes helps with writing at 4x on Ritek G04 disks)
1.0f to 2.0f ->1.1e 4x DVD-R: 4x DVD+R (2x on Ritek G03)

DVD-R at 4x
The U10a and 500a, with all firmwares, should write 4x DVD-R disks at 4x. All burning software will report 4x DVD-R media as 4x and allow you to choose 4x. Unfortunately lots of drives have trouble with burning "unapproved" (i.e. affordable disks like princo) at 4x (15 mins for a full disk), even though the burning software allows 4x to be selected. These disks will burn at 2x, and take 30 mins.
The ability to write at 4x is critically dependant on the individual drive, and varies from batch to batch of certain media. This variability has lead to a lot of confusion and Legend, with people reporting that the 1 disk they burnt "while standing on their head" burned at 4x whilst the one they burned "while it was raining burned at 2x." You often follow threads that state that the 4x problem can be solved by..... followed by a later retraction when the disks later in the batch start to burn at 2x again.

In summary, the Sony does not burn reliably with Princo media at 4x. If your drive does, it is not the phase of the moon, just you have a good drive, or a good batch of disks.

"My drive starts at 4x but slows down later on"

Further confusion is caused by the fact that some software, like Record now max, will initially indicate that it is burning at 4x, despite the drive really burning at 2x. This has lead to a lot of people suspecting buffer under runs or DMA problems. DVDDecryptor is a good check as it will always show the true burning speed, and show you the state of the buffers. If they keep emptying, then you have a data transfer to the drive problem. Get a faster computer, reduce activity on that IDE channel, or generally fiddle about with IDE stuff .

If the buffers are always full but it writes at 2x, then the drive has calibrated on the disk, and decided it is not going to try and burn it at 4x, but dropped back to 2x.

Most people have real problems with Princo Media., and all you can do in this case is burn at 2x or buy diffrent media. None of the firmware versions are likely to help you.

Ritek disks are more likely to write at 4x, but not guaranteed. My drive was happy on all firmwares with most RITEK G04, but wrote at 2x to a batch of Traxdata RITEK G04 disks. You may find that the 1.0d firmware helps you with these marginal disks. I could burn those Traxdata RITEK disks at 4x with 1.0d.

DVD+R
I previously (in this thread) said that I thought that the 1.1c and 1.1e versions of the U10A software would write to DVD+R at 4x. This is not the case (at least with the ARITA disks I tried.) This is a firmware thing. All burning software reports these as 2.4x disks with this firmware.

If you upgrade to 1.0f and above of the 500A/AX software, then you should see the media reported as 4x, and expect to see it burn at 4x.

I have just burned a couple of the ARITA 4x on 1.0g, and I must say that the CDspeed results compare favourably with the best DVD-R results (Pioneer) on Flash's test page.

If you want 4x writing, at a reasonable price, and your DVD player accepts DVD+R disks, these seem to be the best bet on the SONY at the moment.

You can get firmware for the Sony drives in our downloads section.