Debian does not boot ...Crucial/Micron RealSSD m4/C400/P400

Today, my PC did not boot as usual to Debian.  BIOS could not find my /dev/sda and was looking for the netboot image.  I restarted my PC and got into the BIOS boot setting menu.  Hmmm.... my first SDD (/dev/sda) was missing.  My second HDD (/dev/sdb) was there.  But I did not put the Grub boot-loader there.   No wonder it did not boot.

I have a 32GB USB3 stick with the full Debian system.  It is not a live CD image USB stick but a HDD formatted and encrypted system.  Though it is not the fastest system, it is very light and usable.  I plugged it in and powered it up.  It booted OK but /dev/sda was still missing.  While it booted, I saw "ata1: COMRESET failed (errorno=-16)" .  So this ata1 SSD cannot be accessed from BIOS nor Linux.   Sigh ...

Looking around the web under the USB stick system, I saw some people were talking that the loose serial ATA cable sometimes causes this message.   Since my PC is a laptop, It has no flexible cable but has an on-board connector inside for the SSD.

Hoping my problem is just a bad connection problem, I crack opened the back panel of my PC.  The SSD looked fine.  I unplugged it from the connector and reinserted back into the connector.  After repeating this several times to be sure, I closed the back panel and booted.

It boots as expected into Debian.  Looks like everything is fine.
  SMART Error Log Version: 1
  No Errors Logged
Good.

If you have any boot problem like mine, please reinsert your SSD to the connector like I did before you panic.

Good luck.

Osamu

PS: This Crucial/Micron RealSSD m4/C400/P400 M4-CT256M4SSD2 previously had a problem.  A firmware bug made it read-only.  The firmware updates fixed my Debian system on this SSD.  I could fix this without Win*** OS since the firmware update was on a bootable disk image file.