If your PS Vita is still displaying a black screen after performing a hard reset and waiting for 30 seconds, it indicates that the issue might be more serious and could potentially be a hardware problem. Here are a few more steps you can try to troubleshoot the issue:
1. Check for physical damage: Inspect the PS Vita for any signs of physical damage, such as cracks, dents, or water damage. This could help identify if the issue is related to external damage.
2. Attempt a forced recovery mode: Sometimes, entering recovery mode can help resolve software-related issues. To do this, turn off the PS Vita, then press and hold the PS button, power button, and right shoulder button simultaneously for a few seconds. This might reset the system and solve the problem.
3. Try booting into safe mode: Turn off the PS Vita completely, then press and hold the power button, right trigger, and PS button together to boot into safe mode. From there, you may be able to perform a system restore or update the system software.
4. Contact Sony support: If none of the above steps work, it is recommended to contact Sony customer support or take your PS Vita to a professional repair service for further assistance and diagnosis.
If your PS Vita is out of warranty, be prepared for potential repair costs to address the issue. It's essential to consider your options and decide whether repair or replacement is the best course of action.