Hi, i'm fighting with external cache on my ga-486am/s motherboard with AM486DX4-100 (A80486DX4-100SV8B, CV 9538DPB)

I replace faulty cache chips & tag ram to new brand. I think also propertly configure jumpers. System detect 256kB cache memory. All works fine when I use 4x4MB simm memory sticks (total 16MB). But when I install one of 8MB stick, system stuck on post screen with external cache enabled - when disable, system boots.

Boots:

4x4MB + External cache enabled - OK
4x4MB + External cache disabled - OK
1x8MB + External cache enabled - Stuck on boot from HDD and floppy
1x8MB + External cache disabled - OK

What i'm done:

* All memory sticks is good, tested on MemTest86+
* UM612564K-15 SRAM is tested
* TAG Aster AE88128AK-15 SRAM is tested
* Sockets is tested on multimeter

Some pics:

* https://ibb.co/j6TfdKL - mobo with installed 4x4MB
* https://ibb.co/sRjCJgW - cachecheck with installed 4x4MB + external cache enabled
* https://ibb.co/CbNNT7j - mobo with installed 1x8MB
* https://ibb.co/jhc5Qjx - cachecheck with installed 1x8MB + external cache disabled

Is possible 8MB sticks simm is not compatibile with cache?

Any ideas?