Raspberry Pi 3 B+ Problem

I have been trying to convert map data of Spain with !OSMConvert 1.15 for use with !RiscOSM on a Raspberry Pi 3 B+ with RISC OS 5.24 but it fails at a different point with different errors every time I try. I have tried a variety of Integral Ultima Pro and Samsung 32GB micro-SD cards, but this doesn’t cure the problem.
At no point did the temperature of the RPi go above 40C.
The same process works OK using a Raspberry Pi 2 (1st generation) also using RISC OS 5.24.

Errors I get are:

Message from OSMConvert
Error 8515084 in CallGBPB, (SWI OS_GBPB) Command timeout. Called by FC_GetBytes
OK
After restart DiscKnight check says SDFS micro-SD card OK.

Message from OSMConvert
Error 114857 in CallGBPB (SWI OS_GBPB) Bad free space map. Called by FC_GetBytes
OK
followed by:
Message from SDFS
Please insert card RISCOSpi
Cancel/OK
After restart DiscKnight check says SDFS micro-SD card OK.

Message from OSMConvert
Error 33669319 in CallSwi, (SWI OS_Find) Disc error 02 at :0/00000003BA187400 Called by FC_CloseFile
OK
After restart DiscKnight check says SDFS micro-SD card OK.
*Verify OK

Just to add that Bernard has been in touch with me. I have converted the same file fine on an ARMX6, so there isn’t a bug in OSMConvert that gets triggered by this particular data file. OSMConvert does a lot of reading (mainly big chunks of big files) and writing (a mixture of a few big files and thousands of small files, with quite a lot of caching to improve efficiency). There seems to be a problem, therefore, at the OS level in relation to accessing the SD card.

As Bernard has tried several different cards which have all failed, but has succeeded using 5.24 in a Pi 2, it looks like the problem is specific to the Pi 3 B+.

It sounds a lot like “power supply not stable enough” or “SD card not compatible with Pi”. I guess more likely the former, since Samsung cards should work just fine.

I’m using a brand new official 2.5 amp Raspberry Pi PSU.

I have done another test overnight using a different 2.5 amp official Raspberry Pi PSU. The OSMConversion failed about 14 hours in producing this error:

Message from OSMConvert
Error 114857 in CallGBPB (SWI OS_GBPB) Bad free space map.
Called by FC_PutBytes.
OK
After restart DiscKnight check says SDFS micro-SD card OK.
Using 32GB Samsung micro-SD card.
The voltage at the GPIO pins was 5.14v throughout.

Have you tried :-

*verify

[for testing the hardward ie disc]

Yes, *verify already done and OK. See last line of my first post. Multiple micro-SD cards already tried. All show the problem.