Program always ends with "Error: sync: not synced" on W5100S-EVB-Pico

[IakovlevAA]

Hi, I've been trying to flash blink app example for https://github.com/usedbytes/rp2040-serial-bootloader
Unfortunately, I can't get it to work, as serial-flash always throws at the end

Synchronising:
 5 / 5 [=======================================================] 100.00% 59/s 0s
Error: sync: not synced

My steps are:

1. Build rp2040-serial-bootloader on branch with 32k modification
2. Flash .uf2 on Wiznet W5100S-EVB-Pico
3. Build pico-blink-noboot2 according to 32k modification (standalone)
4. ./serial-flash /dev/ttyUSB0 ../pico-blink-noboot2/build/blink_noboot2.elf
5. Getting error
   After that I see no blinking and wiznet stays in bootloader