Guru
Joined: 05/10/2019
Location: United KingdomPosts: 9196
| Posted: 06:34am 17 Jun 2022 |
The Canon doesn't surprise me that much as it will be badge engineered - you don't know who made the memory in it - and it's possible that Canon don't either! The SanDisk does surprise me as they seem to have tight control over their memory sources (I'm not certain that even they actually have their own chip fab though).
If you have a scope it would be instructive to watch the supply voltage actually on the pins of the card socket (solder wires on, don't rely on holding probes, keep them as short as possible and also use the card's GND connection). Watch for a negative-going glitch caused by a high start-up current. You could try soldering 100uF across the card supply pins. Apart from that I can't really think of anything else, after all, they work after a failed initialisation.