Insufficient resources on DFU OTA

Hej,

on trying to update firmware on nrf52832 over the air I'm getting the error message INSUFFICIENT_RESOURCES.

Actually I don't understand the error message because if I generate the bootloader settings page for the firmware image and flash both hex files separately (the firmware and the bl settings page) everything works as expected. For our customers I wan't this firmware image to be updated using DFU OTA so I generate a zip file with nrfutil:

nrfutil pkg generate --hw-version 52 --application-version 1 --application myfirmware.hex --sd-req 0x8c --key-file ../keys/private.pem update_file.zip

I need to say that since our last update we added a ton of features and a huge binary blob of about 60 kB so that the resulting image has a size of 348 kB. Regarding the nrf52 memory layout the firmware image starts at 0x1f000. The bootloader starts at address 0x78000. So from my understanding the firmware exactly fits into the space between 0x1f000 and 0x78000. Correct me if I'm wrong. Do I miss something? Are there any restrictions regarding file size and DFU OTA update?

Best regards

Christian Haake