@hellothere don't want to leave this unanswered.

Prereq:
Have a USB drive or SSD with same or larger capacity than your SD card.
When using an SSD SATA to USB adapter make sure it is fully UASP to get max. transfer/access speed. Here are some hints [1] - also this site has more details as I do provide below.

It goes like this:

Make a full backup of your SD-card (eg. with Win32DiskImager (<- easiest), Clonezilla, ...) to your desktop PC. Put that backup at your USB drive / SSD (again using Win32Diskimager or the tool of your choice) on your desktop PC. Resize the USB partition (only if the USB drive is larger than SD card). Advise the pi to use a different partition after initial booting from /boot, handing over to the USB drive.

When you are done with the backup (Step 1 and 2 from above) attach both (SD card and USB drive) to the Rpi.
Remove any additional USB storage attached to the pi to avoid confusion.
Boot/Power up.
Nothing has changed up to this point.

Note: Following steps are the crucial part - but no worries you have a backup. If something derails, you can back out by using the backup.

Step 3: Optional: Resize the USB partition (if USB drive is larger than SD card).

SSH to your pi as user pi. Type

sudo su

Issue blkid /dev/sda*

blkid /dev/sda* /dev/sda: PTUUID="e006ca92-3704-44b9-a15f-bc56e2171825" PTTYPE="gpt" /dev/sda1: UUID="4832bb70-bb77-4a4a-9d68-5541559df133" TYPE="ext4" PARTUUID="9ec38a7c-ff79-413f-bddc-fc66de260c13"

Note the partition number /dev/sdN on the left which has the TYPE="ext4".

Run with that number resize2fs /dev/sdN (replace N with your number identified, most likely it will be 2).
Wait for process to finish.

Step 4: Advise the kernel to mount a different partition as "root-filesystem".

I underlined the items to REMOVE in RED and those to ADD in GREEN.

The red and green values are different on your machine. Use those. Not those from the example!

SSH to your pi as user pi. Type

sudo su

gets you root.

Issue blkid /dev/sda*
B1.jpg

Will give you a similar output as above.
Note down the value of PARTUUID of partition with TYPE="ext4" (in the example 9ec38a7c-ff79-413f-bddc-fc66de260c13). There should be only one with this type.

Edit fstab (with editor nano (<-- easiest) (or editor of your choice)):

mount /dev/sda1 /mnt # <-- this should be the same sdN as used in resize2fs, will mount the partition from the USB drive. nano /mnt/etc/fstab

You will find something like this:

B2a.jpg

These current PARTUUID point to partitions on your SD card.( You can verify it with blkid /dev/mmcblk0*)

The second entry has to be altered to contain the PARTUUID you noted down before. For example:

B2b.jpg

Again: Use your identified PARTUUID value.
You don't have to keep the lines starting with # (=comment)
Save the file.

Almost done: Then edit cmdline.txt, last step before rebooting:

nano /boot/cmdline.txt

You will find something like:

B3a.jpg

This instructs the kernel to look for the root filesystem at the partition PARTUUID, currently the SD card.

Make it read, change only the PARTUUID, leave everything else as is:

B3b.jpg

Save the file. Reboot... Drum roll, please!

After reboot, ssh to your pi, then check with mount command:

mount | grep sda

Should output something like:

/dev/sda1 on / type ext4 (rw,noatime)

That's it. Revel in your success.

[1] https://jamesachambers.com/raspberry-pi-4-usb-boot-config-guide-for-ssd-flash-drives/

@rasp_renegade

For my RPI 4B+, I bought this one - https://www.amazon.ca/gp/product/B07W6T25Y4/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1.

It has an on/off switch - which the Canakit adapter didn't have, it is manufactured by a reliable (name brand) company and has great user reviews.
Since I have used it, I never have the yellow lightening bolt (low voltage warning) show up in Raspberry Pi OS - a problem I was plagued with in my Raspberry Pi 3B+ setup and generic adapter.

@busywait Thanks!

Hi!
Yes, in general, that is possible. I know from several customers that they did exactly that.

@quicksilver

Thank you, my friend.

@benjaminjay yeah, the official one: https://www.amazon.com/Official-Raspberry-Foundation-Power-Supply/dp/B01LCNF8FU

Nope. This didn't work. The internal resistance of the capacitor is too high to deliver enough current to prevent a power interruption. You get a very low current output for a long time, not a high current output for a short time. I found only very large supercaps such as car audio "stiffening" caps have low enough resistances, and those are about the size of a soda can so it's a no go.

@jediknight36 Replace the power supply. I've had a $5 chinese power supply for my pi2 give me the lightning bolt like 1-2years later. Opening it up, they used very thin wires that just gave out from the thinness and poor solder job. Replaced them with thicker ones and all's good. Zero issues with my official pi power supplies.

@petrockblog Still interested. Sent you an e-mail. Thanks.

@SeraphisCain

What could have caused it to appear momentarily like that, just as I was shutting down?

I wonder if your heater or AC was kicking on at that exact time or maybe a power brownout or if you're using an old surge protector, maybe it time to replace it. Those things don't last forever and can wear out over time from multiple power surges. Also if you're going to replace your surge, you might as well spend a little more and get a Battery Backup which will help with surges and brownouts. I've got this one that I plug my modem/router into and my main Raspberry Pi.

And is it something I should be worried about?

If it only ever happens once, I wouldn't worry about. If it keeps happening, then it could be an issue. Maybe a short in the power cable? Bad surge protector? Dirty power?

@thestarglider said in SNES controller ghosting on Retropie/Kodi etc... An interesting find...:

It would be interesting to know if anyone else had tried an alternative power source to their Pi when they've had issues with ghosting, because in all the threads I have read, I don't remember anyone else bringing it up.

i kinda did :) https://retropie.org.uk/forum/topic/8187/gamepads-making-involuntary-movements-in-emulation-station

the issue is power interference so it figures that changes to power supply or connection can influence it. however it won't fix it for everyone.

I got everything working flawlessly with a different power supply: 5.2V, 3A. :)

@melbmatt50 said in Retropie power switch:

As I mentioned before many of the emulators I am not sure if you can program a hot key to escape back to the main retropie menu like you can in mame4all

more or less any default emulator in retropie should do this by default. there should be no reason to unplug the pi to turn it off whilst retropie is running.

@urko948 Use the official Raspberry Pi power adapter or whatever the Raspberry guys recommend.

@quicksilver said in That God %$#@ Lightning Bolt:

@classicgmr https://www.amazon.com/Mackertop-HSTNN-LA43-PA-1150-22HA-779573-001-761247-002/dp/B01HB44IE6

This is the power supply that I'm using with my pi3, I am also using the super kintaro case. I have had no issues with this power supply and I'm overclocked.

Just an update to reclaim my thread. ;)

This has been working just fine for me. Haven't seen a lightning bolt since I started using it. Only hardwired 3A cables for me from now on. Thank you all for your suggestions. :)

@Lurker thank you for this detail, also super helpful for me. I am considering doing the same thing but using this switch (Pilot Automotive PL-SW26 Performance Toggle Switch with Red Safety Cover https://www.amazon.com/dp/B000GTMUUI/ref=cm_sw_r_cp_api_i_6uZQDbMXHJDGD). I don’t have any electrical experience - can I ask you what the difference would be here given this only has 2 connectors vs the 3 in the other switch?

@creativename i only use the canakits except in my pistation build which need to run a hub and a hdd off of the same power supply and the canakit isnt enough. I use two canakits on my apple iie pi.

@dankcushions I've personally never had any issues with canakit chargers but I also don't overclock