Old Ibook Clamshell Ram Replacement - Ibook doesn't accept new ram

Hello everyone, I'm having a problem with an old iBook G3 Clamshell in Tangerine. Since the installed RAM module wasn't working properly, I decided to replace it. I tried two different 128MB PC100 SD-RAM SO-DIMM modules, one from Siemens and the other from IBM. Neither is accepted; when I enter System Profile on OS 10.0.4, they're flagged as incompatible. The firmware is updated to version 4.17. After removing the RAM block, the Mac runs perfectly with the soldered-in memory, but it only has 64MB. Currently, it's running with two separate partitions, one with OS 9.2.2 and the other with OSX 10.0.4 (the last one booting with less RAM).

Is the RAM really incompatible? What am I doing wrong with the buying of these RAM blocks? Which one should I buy? I also tried to reset the NVRAm from Open Firmware, as well as I asked about the memory from OF, I can attach the result if needed.

Thanks everyone, have a nice day.