I needed to check if files went to a generated image and by accident noticed that 7z is actually quite nice ad-hoc tool for checking such thing:
❯ 7z l efi-part.vfat
7-Zip [64] 16.02 : Copyright (c) 1999-2016 Igor Pavlov : 2016-05-21
p7zip Version 16.02 (locale=en_US.UTF-8,Utf16=on,HugeFiles=on,64 bits,32 CPUs 13th Gen Intel(R) Core(TM) i9-13900KF (B0671),ASM,AES-NI)
Scanning the drive for archives:
1 file, 33521664 bytes (32 MiB)
Listing archive: efi-part.vfat
--
Path = efi-part.vfat
Type = FAT
Physical Size = 33521664
File System = FAT16
Cluster Size = 2048
Free Space = 19079168
Headers Size = 90112
Sector Size = 512
ID = 2421383688
Date Time Attr Size Compressed Name
------------------- ----- ------------ ------------ ------------------------
2024-09-10 20:59:32 D.... EFI
2024-09-10 20:59:32 ....A 14349312 14350336 bzImage
2024-09-10 20:59:32 D.... loader
2024-09-10 20:59:32 D.... loader/entries
2024-09-10 20:59:32 ....A 126 2048 loader/entries/buildroot.conf
------------------- ----- ------------ ------------ ------------------------
2024-09-10 20:59:32 14349438 14352384 2 files, 3 folders