I've searched for it and what I read was not 100% clear to me. Can somebody explain to me how to do it, step by step. What I want to know is,
1. Which utility to use to flash the firmware
2. Do I have to patch it like when crossflashing 1633s to 1653s and if yes, which utility should I use
3. Are there any already patched firmware to download?

Thanks

P.S.
Is the Sony drive not compatible with K-Probe? When I try to do a scan, the read speed stays below 1x (even in Nero) and this is the main reason why I need to crossflash it to a Benq to see if that works.

You need to use BQFlasher to convert you drive to a BenQ. You will find a sticky thread about this in the BenQ forum. You don't need a patched firmware to do it, just the normal BenQ firmware.

KProbe only works with the MTK chipset, not the Philips chipset in the 810A.

Thanks C0deKing. Cross-flash was successful. I will have to stick to Nero CD/DVD Speed to do scans with the Sony (or Benq) drive. However, the quality scores are different from my Liteon 1633 (@1653, CS0T) drive with the involvement of jitter. What I don't understand is how come the scores be lower on the Liteon even though the average and total PI/PIFs are less than the 810a drive. And even if both are scanned at same speed (8x). Can anyone enlighten me on this?