Problem accesing LiteOn drive in USB enclosure

I am in much need of a suggestion here. I have a LiteOn DVD-RW model iHAS122-18 B that i have been using in a non-oem usb enclosure without any problems for several weeks now. But as it is i couldn't leave things alone because the write quality was rather crappy and so i flashed it with firmware from a (electronically identical but with more feature) LiteOn model iHAS524 B. Now i have a big problem it no longer works well on USB enclosure ... it does work perfectly internally, on SATA cable but on USB when i insert a disk in it the computer locks...
I am not happy with this because now i had to swap a HDD with this DVD-RW for it to work and now the HDD works on the USB, which is slower.
Can someone give me any idea what's wrong? The drive reads/writes perfectly but never in the USB. Did i create without wanting a compatibility issue? The USB enclosure works fine with any other DVD-RW or HDD so i can rule it out as the cause.

It is very possible that you caused some issue by flashing with firmware that wasn't intended for the drive. Can you try re-flashing the drive back to a proper firmware and see if that solves the issue?

Actually i'm afraid i cannot do that since there is no "unlocked" firmware for the low-end DVD-RW. Flashing regular firmware from manufacturer will make DVD-RW not detected as it will see hardware do not appear to be the same (even though it really the same). So in less words there also EEPROM memory that must be program to accept firmware for a certain model. There i could find only firmware intended for upgrading low end DVD-RW to high end with more functions only requierement that it use the same controller chip. And indeed it works. It is true, when using USB enclosure write quality was poor but never had system lock problem when insert blank disk. Now when being forced by situation to use the SATA interface write quality is good not great as my old LG i had before but good but unable to go back to USB-to-SATA converter or enclosure.