Thank you to all who posted here providing valuable information.
Conclusion is as follow: the issue with SSD drives not being mounted on router's reboot is caused by combinations of:
1. routers are different in speed of boot (how fast power is delivered to USB port)
2. some SATA enclosures may "work" and others may not, depending on the bridges used in them
3. the most safe option is to use enclosures or USB to SATA adapters with own power supply
I think it could be useful to have in this forum a pinned thread with confirmed working SSD drives closures, NVMe, with a table like:
| Asus model | SSD enclosure or NVME disk (with detail what exact model) | AsusWRT Merlin version |
If there was something like this, I would avoid buying 2 SSD enclosures that don't work with my Asus RT-AX88U Pro![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Another thought: it's a pity that it is impossible to somehow script the physical action of removing and plugging again a cable into USB port. If it would be possible then it can be used as a fix for the issue.
Conclusion is as follow: the issue with SSD drives not being mounted on router's reboot is caused by combinations of:
1. routers are different in speed of boot (how fast power is delivered to USB port)
2. some SATA enclosures may "work" and others may not, depending on the bridges used in them
3. the most safe option is to use enclosures or USB to SATA adapters with own power supply
I think it could be useful to have in this forum a pinned thread with confirmed working SSD drives closures, NVMe, with a table like:
| Asus model | SSD enclosure or NVME disk (with detail what exact model) | AsusWRT Merlin version |
If there was something like this, I would avoid buying 2 SSD enclosures that don't work with my Asus RT-AX88U Pro
Another thought: it's a pity that it is impossible to somehow script the physical action of removing and plugging again a cable into USB port. If it would be possible then it can be used as a fix for the issue.