RPi4 died SD card weirdness?

Hello,

I was on holidays far from home and wanted to have an ssh session on my 
RPI4 running NetBSD 11.0. I noticed it was unreachable. When I arrived 
home I connected a HDMI monitor, it did not show anything and restarted 
it. It get stuck on the raspberry fruit image showing this error, not 
even reaching the NetBSD bootloader:

I write it manually:

"Synchronous Exception at 00000000387E93CC"

Repeated the restart several times with same result.

I removed SD card, placed into a card reader and examined it on a Acer 
Aspire One NetBSD old machine.

/dev/dk2 is the FAT partition and /dev/dk3 is the FFS NetBSD partition.

dmesg suggested dk3 was not clean and should be repaired, and even it 
should not be the culprit of the RPi4 boot error, I run an fsck session 
and it repaired several errors.

Somewhere I read  that there are reported issues with the pftf UEFI 
RPI_EFI.fd file that gets corrupted and replacing it will solve the 
problem.

I backuped it first and unmounted the partition. I mounted again and 
surprisingly the backuped file had disapeared.

I was surprised, created a new text file just to test, sync, sync, sync, 
unmounted, mounted again and the file DISAPEARED.[    51,661165] umass0 
at uhub4 port 1 configuration 1 interface 0

same weirdness occurs on the FFS partition, nothig is written.


here you have an example:


netbsd-acer# uname -a
NetBSD netbsd-acer.home 11.0 NetBSD 11.0 (GENERIC) #0: Thu Jul 30 
15:23:12 UTC 2026 
[email protected]:/usr/src/sys/arch/amd64/compile/GENERIC amd64
netbsd-acer#



[    51,661165] umass0: SanDisk (0x0781) SDDR-B531 (0xcfcb), rev 
2.10/29.20, addr 3
[    51,661165] umass0: using SCSI over Bulk-Only
[    51,661165] scsibus0 at umass0: 2 targets, 1 lun per target
[    52,081178] sd0 at scsibus0 target 0 lun 0: <SanDisk, SDDR-B531, 
2920> disk removable
[    52,091177] sd0: fabricating a geometry
[    52,091177] sd0: 119 GB, 121942 cyl, 64 head, 32 sec, 512 bytes/sect 
x 249737216 sectors
[    52,091177] sd0: fabricating a geometry
[    52,121177] sd0: GPT GUID: 987939cb-c08e-4614-88c3-6749b5d3104f
[    52,121177] dk2 at sd0: "EFI", 163840 blocks at 32768, type: msdos
[    52,121177] dk3 at sd0: "netbsd-root", 249536512 blocks at 196608, 
type: ffs




netbsd-acer# mount /dev/dk2 disco_fat/
netbsd-acer# mount -v
/dev/dk0 on / type ffs (local, root file system, fsid: 0xa800/0x78b, 
reads: sync 229953 async 0, writes: sync 7043 async 4489)
tmpfs on /tmp type tmpfs (local, fsid: 0xab01/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
kernfs on /kern type kernfs (local, fsid: 0x8b02/0x1d28b, reads: sync 0 
async 0, writes: sync 0 async 0)
ptyfs on /dev/pts type ptyfs (local, fsid: 0x7b03/0x6b7b, reads: sync 0 
async 0, writes: sync 0 async 0)
procfs on /proc type procfs (local, fsid: 0x1b04/0x1ae1b, reads: sync 0 
async 0, writes: sync 0 async 0)
tmpfs on /var/shm type tmpfs (local, fsid: 0xab05/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
/dev/dk2 on /root/disco_fat type msdos (local, fsid: 0xa802/0x764f, 
reads: sync 0 async 0, writes: sync 0 async 0)
netbsd-acer# echo "this is a hell" > test1
netbsd-acer# cat test1
this is a hell
netbsd-acer# echo "this is a hell2" > test2
netbsd-acer# cat test2
this is a hell2
netbsd-acer# sync
netbsd-acer# mount -v
/dev/dk0 on / type ffs (local, root file system, fsid: 0xa800/0x78b, 
reads: sync 237391 async 0, writes: sync 7154 async 4670)
tmpfs on /tmp type tmpfs (local, fsid: 0xab01/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
kernfs on /kern type kernfs (local, fsid: 0x8b02/0x1d28b, reads: sync 0 
async 0, writes: sync 0 async 0)
ptyfs on /dev/pts type ptyfs (local, fsid: 0x7b03/0x6b7b, reads: sync 0 
async 0, writes: sync 0 async 0)
procfs on /proc type procfs (local, fsid: 0x1b04/0x1ae1b, reads: sync 0 
async 0, writes: sync 0 async 0)
tmpfs on /var/shm type tmpfs (local, fsid: 0xab05/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
/dev/dk2 on /root/disco_fat type msdos (local, fsid: 0xa802/0x764f, 
reads: sync 0 async 0, writes: sync 0 async 0)
netbsd-acer# mount -v |grep dk2
/dev/dk2 on /root/disco_fat type msdos (local, fsid: 0xa802/0x764f, 
reads: sync 0 async 0, writes: sync 0 async 0)
netbsd-acer# cd ..
netbsd-acer# pwd
/
netbsd-acer# cd
netbsd-acer# umount disco_fat/
netbsd-acer# mount /dev/dk2 disco_fat/
netbsd-acer# cd disco_fat/
netbsd-acer# ls
EFI                                     config.txt
LICENCE.broadcom                        config.txt-bak
RPI4_UEFI_Firmware_v1.50.zip            dtb
RPI_EFI.fd                              firmware
RPI_EFI.fd-bak                          fixup.dat
Readme.md                               fixup4.dat
bcm2711-rpi-4-b.dtb                     fixup4cd.dat
bcm2711-rpi-400.dtb                     fixup_cd.dat
bcm2711-rpi-cm4.dtb                     netbsd.img
boot                                    overlays
boot.cfg                                start.elf
bootcode.bin                            start4.elf
cmdline.txt                             start4cd.elf
cmdline.txt-bak                         start_cd.elf
netbsd-acer# cat test1
cat: test1: No such file or directory
netbsd-acer# cat test2
cat: test2: No such file or directory
netbsd-acer# mount -v
/dev/dk0 on / type ffs (local, root file system, fsid: 0xa800/0x78b, 
reads: sync 247707 async 0, writes: sync 7273 async 4828)
tmpfs on /tmp type tmpfs (local, fsid: 0xab01/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
kernfs on /kern type kernfs (local, fsid: 0x8b02/0x1d28b, reads: sync 0 
async 0, writes: sync 0 async 0)
ptyfs on /dev/pts type ptyfs (local, fsid: 0x7b03/0x6b7b, reads: sync 0 
async 0, writes: sync 0 async 0)
procfs on /proc type procfs (local, fsid: 0x1b04/0x1ae1b, reads: sync 0 
async 0, writes: sync 0 async 0)
tmpfs on /var/shm type tmpfs (local, fsid: 0xab05/0x69ab, reads: sync 0 
async 0, writes: sync 0 async 0)
/dev/dk2 on /root/disco_fat type msdos (local, fsid: 0xa802/0x764f, 
reads: sync 15 async 0, writes: sync 0 async 0)
netbsd-acer#


Any help will be apreciated.

Regards.