Unable to read sectors from sd card on STM32U575ZI

[kk9]

Hello I'm trying read sector numer 0 from SD card. I use 4-bit mode for sd card reading. My MCU is on Nucleo development board. Card is correctly initialized but when I'm trying read sector I get zeros in buffer and maybe 10 random not-zero bytes. What do I incorrect?
After restart I get the same values when I use the same sd-card. But when I use other card - I get other incorrect data.

[TDK]

0 is a valid value to be in memory. Do you think it should be something else? Why?

A better test would be to erase the block, write to it, then read it out and verify content.

initialize the buffer to something to ensure new data is actually populated.