Help me debug: flash programming successful and verified; program does not run
In such low debug resource environment, every tool must be utilized. In my case, this was the in circuit programmer. I used it to download images of the flash. 

 sudo avrdude -p atmega8 -c usbasp -U flash:r:file_name:r


Then using dhex any byte value differences became evident, leading to the conclusion that the flash programming fucntions from avr-libc expect unsigned chars and I am using signed chars.

Yey, my very first bootloader works.