I don't know why you need the recovery mode. The flashing software (for example RKBatchTool) can put your boyue in the correct mode (if I'm not mistaken it's bootloader not recovery mode). I think boyue T62 also can be put in the bootloader mode by turning it on while holding one of it's buttons (don't know which one).
It's possible that you were able to put the device in the correct mode but the flushing tool can't see it because your pc doesn't have drivers installed. The package from icarus contains necessary drivers. Also I see drivers here:
https://www.mobileread.com/forums/sh...d.php?t=245888 (probably the same ones). And according to "6- How to unbrick your device" from that link you will get the bootloader mode using the Refresh button.