[avr-chat] avrdude - strange behaviour when binary don't start @0x0000

[Massimiliano Cialdi]

I use avrdude 5.10.

I compile a simple binary starting from 0x7000 (unsing LDFLAGS+=-Ttext=0x7000). This simple binary will become my bootloader.

it is 102 bytes long

when I try to flash it I obtain:

$ avrdude -v -p m32 -F -c dragon_isp -B 0.4 -P usb -U flash:w:boot.hex:i

[...]
avrdude: AVR device initialized and ready to accept instructions

Reading | ################################################## | 100% 0.15s

avrdude: Device signature = 0x1e9502
avrdude: safemode: lfuse reads as 3F
avrdude: safemode: hfuse reads as C8
avrdude: NOTE: FLASH memory has been specified, an erase cycle will be performed
         To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "boot.hex"
avrdude: writing flash (28774 bytes):

Writing | ################################################## | 100% 0.12s

avrdude: 28774 bytes of flash written
avrdude: verifying flash memory against boot.hex:
avrdude: load data flash data from input file boot.hex:
avrdude: input file boot.hex contains 28774 bytes
avrdude: reading on-chip flash data:

Reading | ################################################## | 100% 8.33s

avrdude: verifying ...
avrdude: 28774 bytes of flash verified


it is a strange behaviour: it read boot.hex file as it contains 28774 byets (that is 28K + 102).
although it writes only 102 bytes in the correct posizion (in fact write time is so short, and I can verify with an logic signal analyzer with SPI bus decode), but verify whole 28774 bytes.

This is a problem when multiple writes are performed:
$ avrdude -v -p m32 -F -c dragon_isp -B 0.4 -P usb -U flash:w:app.hex:i -U flash:w:boot.hex:i

abviously it fails boot verify

is that a bug?

thanks