Re: RPi4 died SD card weirdness?

Ramiro Aceves <[email protected]>
Newsgroups gmane.os.netbsd.general
Message-ID <[email protected]>

El 24/8/26 a las 0:29, RVP escribió:
> On Sun, 23 Aug 2026, Ramiro Aceves wrote:
> 
>> Sorry, I placed commands not in the mount directory. This is the right test:
>>
>> netbsd-acer# pwd
>> /root
>> netbsd-acer# mount /dev/dk2 disco_fat/
>> netbsd-acer# cd disco_fat/
>> netbsd-acer# echo "this is a nightmare" > test
>> netbsd-acer# ls
>> EFI                             boot.cfg                        fixup4cd.dat
>> LICENCE.broadcom                bootcode.bin                    fixup_cd.dat
>> RPI4_UEFI_Firmware_v1.50.zip    cmdline.txt                     netbsd.img
>> RPI_EFI.fd                      cmdline.txt-bak                 overlays
>> RPI_EFI.fd-bak                  config.txt                      start.elf
>> Readme.md                       config.txt-bak                  start4.elf
>> bcm2711-rpi-4-b.dtb             dtb                             start4cd.elf
>> bcm2711-rpi-400.dtb             firmware                        start_cd.elf
>> bcm2711-rpi-cm4.dtb             fixup.dat                       test
>> boot                            fixup4.dat
>> netbsd-acer# cat test
>> this is a nightmare
>> netbsd-acer# cd ..
>> netbsd-acer# umount disco_fat/
>> netbsd-acer# pwd
>> /root
>> netbsd-acer# mount /dev/dk2 disco_fat/
>> netbsd-acer# cd disco_fat/
>> netbsd-acer# ls
>> EFI                             boot.cfg                        fixup4cd.dat
>> LICENCE.broadcom                bootcode.bin                    fixup_cd.dat
>> RPI4_UEFI_Firmware_v1.50.zip    cmdline.txt                     netbsd.img
>> RPI_EFI.fd                      cmdline.txt-bak                 overlays
>> RPI_EFI.fd-bak                  config.txt                      start.elf
>> Readme.md                       config.txt-bak                  start4.elf
>> bcm2711-rpi-4-b.dtb             dtb                             start4cd.elf
>> bcm2711-rpi-400.dtb             firmware                        start_cd.elf
>> bcm2711-rpi-cm4.dtb             fixup.dat
>> boot                            fixup4.dat
>> netbsd-acer# cat test
>> cat: test: No such file or directory
>> netbsd-acer#
>>
> 
> Yes, I've heard of this exact same error of some SD devices becoming
> "read-only".  Back in ~2011 or so, this was reported on xda-developers in
> the ViewSonic G-Tablet forums. This tablet has with 16 GB of internal storage.
> Most, I believe came with eMMC, but, a few others had an SDHC device (same
> capacity). And, some SDHC ones exhibited this exact same failure mode.
> Android would keep writing, and as long as all the I/O was taking place on
> the FS cache, it all looked OK. But the kernel would panic when it noticed
> the inconsistency between the in-cache data and the on-disk stuff.
> 
> I got in touch with Pierre Ossman (Linux SDcard drivers), and he hadn't seen
> this failure either, but diagnosed it as some weird HW issue.
> 
> -RVP
> 
> PS. Try seeing if a `dd' with `oflag=direct' with a very large file (10GB)
> provokes an error.

Hi RVP, many thanks for your findings. I am  now backuping the SD contents, it seems that it can be read with no apparent problems. After that I will 
make the dd test directly to the SD and see what happens.

Regards.
Ramiro.
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