Can you please try esptool --no-stub option to see if that is the issue? V4 esptool always works and V5 always fails? If only stub fails I have a suspicion that CPU clock increase is the root cause, I can fix that quite soon, but need it to be tested if possible. If you are willing to try, can you ...

Hello @vbpieter, can you please tell me if you use UART or USB-Serial-JTAG for flashing? Also esptool version you have in the esp-idf v5.5.5, thanks.