Wait...You only need to set _RAMBASE to 1M..., and don't need to touch CONFIG_MAX_TOP_MEM_K, because at the time all ram mtrr and etc are initialized well...
Another problem put the payload on somewhere after may cause the problem for final kerenal..., kernel need to start from 1M....?
So We may need to 1. _RAMBASE for linuxbios_ram ... from 1M or 0x4000 2. _PAYLOAD_BASE it should be somewhere safe for all... a. sth place before 0xa0000, or b. last Mbytes before end of TOM...
payloads will be 1. Etherboot, zelf 2. FILO, 3. OpenBIOS 4. zelf from kernel and initram disk...less than 4Mbyte or 16Mbyte...
How about compress ratio for nrv2b?
YH