can't load anymore sketches to the 85, so apparently something in the fade sketch is causing the error
That's very unlikely. The programmer holds the target in reset while the program is uploaded. There really is no way the existing program can cause a problem.
This...
avrdude: please define PAGEL and BS2 signals in the configuration file for part ATtiny85
...is next. Locate your "avrdude.conf" file. It should be here...
{ArduinoRoot}\hardware\tools\avr\etc
Make a backup copy in case something goes wrong.
Open the file in your favorite text editor.
Search for "ATtiny85".
Replace the ATtiny85 section with this...
#------------------------------------------------------------
# ATtiny85
#------------------------------------------------------------
part
id = "t85";
desc = "ATtiny85";
has_debugwire = yes;
flash_instr = 0xB4, 0x02, 0x12;
eeprom_instr = 0xBB, 0xFF, 0xBB, 0xEE, 0xBB, 0xCC, 0xB2, 0x0D,
0xBC, 0x02, 0xB4, 0x02, 0xBA, 0x0D, 0xBB, 0xBC,
0x99, 0xE1, 0xBB, 0xAC;
## no STK500 devcode in XML file, use the ATtiny45 one
stk500_devcode = 0x14;
## avr910_devcode = ?;
## Try the AT90S2313 devcode:
avr910_devcode = 0x20;
signature = 0x1e 0x93 0x0b;
reset = io;
chip_erase_delay = 4500;
pgm_enable = "1 0 1 0 1 1 0 0 0 1 0 1 0 0 1 1",
"x x x x x x x x x x x x x x x x";
chip_erase = "1 0 1 0 1 1 0 0 1 0 0 x x x x x",
"x x x x x x x x x x x x x x x x";
timeout = 200;
stabdelay = 100;
cmdexedelay = 25;
synchloops = 32;
bytedelay = 0;
pollindex = 3;
pollvalue = 0x53;
predelay = 1;
postdelay = 1;
pollmethod = 1;
hvsp_controlstack =
0x4C, 0x0C, 0x1C, 0x2C, 0x3C, 0x64, 0x74, 0x66,
0x68, 0x78, 0x68, 0x68, 0x7A, 0x6A, 0x68, 0x78,
0x78, 0x7D, 0x6D, 0x0C, 0x80, 0x40, 0x20, 0x10,
0x11, 0x08, 0x04, 0x02, 0x03, 0x08, 0x04, 0x00;
hventerstabdelay = 100;
hvspcmdexedelay = 0;
synchcycles = 6;
latchcycles = 1;
togglevtg = 1;
poweroffdelay = 25;
resetdelayms = 1;
resetdelayus = 0;
hvleavestabdelay = 100;
resetdelay = 25;
chiperasepolltimeout = 40;
chiperasetime = 0;
programfusepolltimeout = 25;
programlockpolltimeout = 25;
memory "eeprom"
size = 512;
paged = no;
page_size = 4;
min_write_delay = 4000;
max_write_delay = 4500;
readback_p1 = 0xff;
readback_p2 = 0xff;
read = "1 0 1 0 0 0 0 0 0 0 0 x x x x a8",
"a7 a6 a5 a4 a3 a2 a1 a0 o o o o o o o o";
write = "1 1 0 0 0 0 0 0 0 0 0 x x x x a8",
"a8 a6 a5 a4 a3 a2 a1 a0 i i i i i i i i";
loadpage_lo = " 1 1 0 0 0 0 0 1",
" 0 0 0 0 0 0 0 0",
" 0 0 0 0 0 0 a1 a0",
" i i i i i i i i";
writepage = " 1 1 0 0 0 0 1 0",
" 0 0 x x x x x a8",
" a7 a6 a5 a4 a3 a2 0 0",
" x x x x x x x x";
mode = 0x41;
delay = 6;
blocksize = 4;
readsize = 256;
;
memory "flash"
paged = yes;
size = 8192;
page_size = 64;
num_pages = 128;
min_write_delay = 4500;
max_write_delay = 4500;
readback_p1 = 0xff;
readback_p2 = 0xff;
read_lo = " 0 0 1 0 0 0 0 0",
" 0 0 0 0 a11 a10 a9 a8",
" a7 a6 a5 a4 a3 a2 a1 a0",
" o o o o o o o o";
read_hi = " 0 0 1 0 1 0 0 0",
" 0 0 0 0 a11 a10 a9 a8",
" a7 a6 a5 a4 a3 a2 a1 a0",
" o o o o o o o o";
loadpage_lo = " 0 1 0 0 0 0 0 0",
" 0 0 0 x x x x x",
" x x x a4 a3 a2 a1 a0",
" i i i i i i i i";
loadpage_hi = " 0 1 0 0 1 0 0 0",
" 0 0 0 x x x x x",
" x x x a4 a3 a2 a1 a0",
" i i i i i i i i";
writepage = " 0 1 0 0 1 1 0 0",
" 0 0 0 0 a11 a10 a9 a8",
" a7 a6 a5 x x x x x",
" x x x x x x x x";
mode = 0x41;
delay = 6;
blocksize = 32;
readsize = 256;
;
# ATtiny85 has Signature Bytes: 0x1E 0x93 0x08.
memory "signature"
size = 3;
read = "0 0 1 1 0 0 0 0 0 0 0 x x x x x",
"x x x x x x a1 a0 o o o o o o o o";
;
memory "lock"
size = 1;
write = "1 0 1 0 1 1 0 0 1 1 1 x x x x x",
"x x x x x x x x 1 1 i i i i i i";
read = "0 1 0 1 1 0 0 0 0 0 0 0 0 0 0 0",
"0 0 0 0 0 0 0 0 o o o o o o o o";
min_write_delay = 9000;
max_write_delay = 9000;
;
memory "lfuse"
size = 1;
write = "1 0 1 0 1 1 0 0 1 0 1 0 0 0 0 0",
"x x x x x x x x i i i i i i i i";
read = "0 1 0 1 0 0 0 0 0 0 0 0 0 0 0 0",
"x x x x x x x x o o o o o o o o";
min_write_delay = 9000;
max_write_delay = 9000;
;
memory "hfuse"
size = 1;
write = "1 0 1 0 1 1 0 0 1 0 1 0 1 0 0 0",
"x x x x x x x x i i i i i i i i";
read = "0 1 0 1 1 0 0 0 0 0 0 0 1 0 0 0",
"x x x x x x x x o o o o o o o o";
min_write_delay = 9000;
max_write_delay = 9000;
;
memory "efuse"
size = 1;
write = "1 0 1 0 1 1 0 0 1 0 1 0 0 1 0 0",
"x x x x x x x x x x x x x x x i";
read = "0 1 0 1 0 0 0 0 0 0 0 0 1 0 0 0",
"x x x x x x x x o o o o o o o o";
min_write_delay = 9000;
max_write_delay = 9000;
;
memory "calibration"
size = 2;
read = "0 0 1 1 1 0 0 0 0 0 0 x x x x x",
"0 0 0 0 0 0 0 a0 o o o o o o o o";
;
;
Save and close the file.
Restart the Arduino IDE.
Try again with one of the first three processors.