Well, 20A1P KLOP FBL EOS EHOT should be fine for firmware. There are also BenQ firmwares available for this drive. DW1800 / DW2000, non-litescribe version and CodeKing also made some Fast Burn Lite firmware for those.
There’s other, more simple, possibilities.
The computer’s power supply may experience a rail sag or it may be outputting noisy power.
The drive may dislike its IDE ribbon cable. This is especially true of round cables.
Most DVD writers dislike the “cable select” position, but some prefer it, and when they do that, it can indicate that the IDE cable is poor.
Cable, jumper, and power supply are all possible causes of disc recognizance issues.
The drive has a power circuit, but so does the computer and a problem could be at either end.
The drive has a controller, but so does the computer and a problem could be at either end.
There’s also the cables in between.
After this post, I’m “out of ammo”
The “P” model is a stripped version of the “H” model; and, apparently, this was not done with grace. The power circuit aboard the “P” model is lesser. The “P” is more touchy for both voltage and temperature. Given that, it is also more easily “irked” by the quality of its “IDE” cable. My own example is prone to reading poorly when it gets warm, but its litescribe cousins don’t do any of that.
In this example is a 50/50 chance that the drive is giving an accurate warning about the power supply and/or the temperature inside your computer.
So, you have the right firmware, but it could be good to inspect the drive’s operating environment. Fixing a flaw there could impact all aspects of your computer or perhaps only its longevity.
Somehow I managed to fix my 20A1P. It still won’t read well when its warm.
Of course its not impossible that firmware is related to this problem, yet not the cause of the problem.
As an example of that. . . My old 1693s won’t read Verbatim +R if it attempts to do so at a higher speed than 8x. Fortunately media type for it also had a read speed control selection via software, and using the 8x dvd rom setting for DVD+R plus bitsetting DVD+R to DVD ROM, in combination, also caused all of its reading difficulties to vanish. This only worked with one of the many possible firmware selections. Although its a “touchy” drive, one (only one) firmware selection did increase environmental tolerances and that drive still works just fine today, after many years of service. Unfortunately, I cannot upgrade the firmware without returning its former “touchy” behaviors. Likewise, for the 18A1P/20A1P, perhaps the related BenQ firmware is worth exploration. I don’t know.
That’s it. I’m out of ideas.