I now understand your configuration.
1. Have you hooked up the UART on GPIOs 14 & 15? If so, what does it show? I would recommend removing "quiet" from cmdline.txt and adding "ignore_loglevel", so that all kernel log output is echoed while you debug this problem.
2. What are you using to determine that the system as "locked up", given that the activity LED is blinking?
3. When you plug in an SD card, the kernel should log some information about it, including the card's class. See if you can capture this information for good and bad cards, either over the UART or by taking photos of any display you have.
1. Have you hooked up the UART on GPIOs 14 & 15? If so, what does it show? I would recommend removing "quiet" from cmdline.txt and adding "ignore_loglevel", so that all kernel log output is echoed while you debug this problem.
2. What are you using to determine that the system as "locked up", given that the activity LED is blinking?
3. When you plug in an SD card, the kernel should log some information about it, including the card's class. See if you can capture this information for good and bad cards, either over the UART or by taking photos of any display you have.
Statistics: Posted by PhilE — Tue Feb 10, 2026 8:51 am