Here is the problem:
starting with SDCC, I install the win 32 package, Anyedit as IDE, then create the .hex file of Tiny bootloader (by mplab), and burn the 16F877 with it (by icprog). First try, a simple test file ([found here-> http://www.pictec.org/dotclear/\]) with RS232 link, burn by the tiny app: all works (compilation, links and so on..), tiny find the pic, load the prog very fast, and the pic link the terminal and works perfect, life is beautiful...
...little changes later, new hex, but impossible to connect the tiny app!
In fact, the first prog I burn (after the bootloader) have change the 3 first words (wich jump to the end of the last bank to the bootloader) by the classic "goto start". I tried to understand the PIC 18 files (crtoi.c, etc..) but the spirit seemed to be different between the 2 families (PIC14 and PIC16).
Is there something easy to do (directive?) to tell the compiler or the linker to not touch these 3 first bytes ??
OK, I tested another bootloader.hex (always tiny) as suggested by JP Mandon (http://jmandon.free.fr/dotclear/index.php?2006/11/11/2-tiny-bootloader) wich seemed to work properly...life is still beautiful!